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Java-based LeetCode algorithm problem solutions, regularly updated.

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LeetCode-in-Java

Maven Central MIT License Java CI Maintainability Rating javadoc

Java-based LeetCode algorithm problem solutions, regularly updated.

Installation

To configure your Maven project, add the following code to your pom.xml file:

<dependencies>
  <dependency>
    <groupId>com.github.javadev</groupId>
    <artifactId>leetcode-in-java</artifactId>
    <version>1.37</version>
  </dependency>
  ...
</dependencies>

Gradle configuration:

implementation 'com.github.javadev:leetcode-in-java:1.37'

"For coding interview preparation, LeetCode is one of the best online resource providing a rich library of more than 300 real coding interview questions for you to practice from using one of the 7 supported languages - C, C++, Java, Python, C#, JavaScript, Ruby."

Data Structure II

Day 1 Array
0136 Single Number Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Big_O_Time_O(N)_Space_O(1) 1 99.86
0169 Majority Element Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Sorting, Counting, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1) 1 99.89
0015 3Sum Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n*log(n))_Space_O(n^2) 29 72.02

Day 2 Array
0075 Sort Colors Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n)_Space_O(1) 0 100.00
0056 Merge Intervals Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n) 7 98.37
0706 Design HashMap Easy Array, Hash_Table, Design, Linked_List, Hash_Function 13 95.71

Day 3 Array
0119 Pascal's Triangle II Easy Array, Dynamic_Programming 0 100.00
0048 Rotate Image Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Big_O_Time_O(n^2)_Space_O(1) 0 100.00
0059 Spiral Matrix II Medium Array, Matrix, Simulation 0 100.00

Day 4 Array
0240 Search a 2D Matrix II Medium Top_100_Liked_Questions, Array, Binary_Search, Matrix, Divide_and_Conquer, Big_O_Time_O(n+m)_Space_O(1) 5 99.92
0435 Non-overlapping Intervals Medium Array, Dynamic_Programming, Sorting, Greedy 96 47.37

Day 5 Array
0334 Increasing Triplet Subsequence Medium Array, Greedy 2 99.33
0238 Product of Array Except Self Medium Top_100_Liked_Questions, Array, Prefix_Sum, Big_O_Time_O(n^2)_Space_O(n) 1 99.66
0560 Subarray Sum Equals K Medium Top_100_Liked_Questions, Array, Hash_Table, Prefix_Sum, Big_O_Time_O(n)_Space_O(n) 21 98.97

Day 6 String
0415 Add Strings Easy String, Math, Simulation 3 82.41
0409 Longest Palindrome Easy String, Hash_Table, Greedy 2 92.90

Day 7 String
0290 Word Pattern Easy String, Hash_Table 1 97.26
0763 Partition Labels Medium String, Hash_Table, Greedy, Two_Pointers, Big_O_Time_O(n)_Space_O(1) 1 100.00

Day 8 String
0049 Group Anagrams Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, String, Hash_Table, Sorting, Big_O_Time_O(n*k_log_k)_Space_O(n) 6 97.61
0043 Multiply Strings Medium String, Math, Simulation 1 100.00

Day 9 String
0187 Repeated DNA Sequences Medium String, Hash_Table, Bit_Manipulation, Sliding_Window, Hash_Function, Rolling_Hash 29 77.11
0005 Longest Palindromic Substring Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) 7 97.82

Day 10 Linked List
0002 Add Two Numbers Medium Top_100_Liked_Questions, Top_Interview_Questions, Math, Linked_List, Recursion, Big_O_Time_O(max(N,M))_Space_O(max(N,M)), AI_can_be_used_to_solve_the_task 1 100.00
0142 Linked List Cycle II Medium Top_100_Liked_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1) 0 100.00

Day 11 Linked List
0160 Intersection of Two Linked Lists Easy Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(M+N)_Space_O(1) 1 99.92
0082 Remove Duplicates from Sorted List II Medium Two_Pointers, Linked_List 0 100.00

Day 12 Linked List
0024 Swap Nodes in Pairs Medium Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1) 0 100.00
0707 Design Linked List Medium Design, Linked_List 10 70.60

Day 13 Linked List
0025 Reverse Nodes in k-Group Hard Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(k) 0 100.00
0143 Reorder List Medium Two_Pointers, Stack, Linked_List, Recursion 2 72.59

Day 14 Stack Queue
0155 Min Stack Medium Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Big_O_Time_O(1)_Space_O(N) 4 96.54
1249 Minimum Remove to Make Valid Parentheses Medium String, Stack 13 94.62
1823 Find the Winner of the Circular Game Medium Array, Math, Simulation, Recursion, Queue 3 64.85

Day 15 Tree
0108 Convert Sorted Array to Binary Search Tree Easy Top_Interview_Questions, Array, Tree, Binary_Tree, Binary_Search_Tree, Divide_and_Conquer 0 100.00
0105 Construct Binary Tree from Preorder and Inorder Traversal Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Tree, Binary_Tree, Divide_and_Conquer, Big_O_Time_O(N)_Space_O(N) 1 96.33
0103 Binary Tree Zigzag Level Order Traversal Medium Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree 1 95.00

Day 16 Tree
0199 Binary Tree Right Side View Medium Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree 1 94.57
0113 Path Sum II Medium Depth_First_Search, Tree, Binary_Tree, Backtracking 1 100.00
0450 Delete Node in a BST Medium Tree, Binary_Tree, Binary_Search_Tree 0 100.00

Day 17 Tree
0230 Kth Smallest Element in a BST Medium Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(n)_Space_O(n) 0 100.00
0173 Binary Search Tree Iterator Medium Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator 18 84.18

Day 18 Tree
0236 Lowest Common Ancestor of a Binary Tree Medium Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n) 6 100.00
0297 Serialize and Deserialize Binary Tree Hard String, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Design 7 98.13

Day 19 Graph
0997 Find the Town Judge Easy Array, Hash_Table, Graph 3 80.64
1557 Minimum Number of Vertices to Reach All Nodes Medium Graph 8 99.94
0841 Keys and Rooms Medium Depth_First_Search, Breadth_First_Search, Graph 3 51.54

Day 20 Heap Priority Queue
0215 Kth Largest Element in an Array Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Quickselect, Big_O_Time_O(n*log(n))_Space_O(log(n)) 5 70.82
0347 Top K Frequent Elements Medium Top_100_Liked_Questions, Array, Hash_Table, Sorting, Heap_Priority_Queue, Counting, Divide_and_Conquer, Quickselect, Bucket_Sort, Big_O_Time_O(n*log(n))_Space_O(k) 9 97.93

Day 21 Heap Priority Queue
0451 Sort Characters By Frequency Medium String, Hash_Table, Sorting, Heap_Priority_Queue, Counting, Bucket_Sort 13 89.63
0973 K Closest Points to Origin Medium Array, Math, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Geometry, Quickselect 4 98.26

Algorithm I

Day 1 Binary Search
0704 Binary Search Easy Top_100_Liked_Questions, Array, Binary_Search 0 100.00
0278 First Bad Version Easy Binary_Search, Interactive 15 87.89
0035 Search Insert Position Easy Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) 0 100.00

Day 2 Two Pointers
0977 Squares of a Sorted Array Easy Array, Sorting, Two_Pointers 1 100.00
0189 Rotate Array Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Two_Pointers, Big_O_Time_O(n)_Space_O(1) 0 100.00

Day 3 Two Pointers
0283 Move Zeroes Easy Top_100_Liked_Questions, Array, Two_Pointers, Big_O_Time_O(n)_Space_O(1) 2 83.99
0167 Two Sum II - Input Array Is Sorted Medium Array, Binary_Search, Two_Pointers 1 99.21

Day 4 Two Pointers
0344 Reverse String Easy String, Two_Pointers, Recursion 1 99.91
0557 Reverse Words in a String III Easy String, Two_Pointers 4 97.75

Day 5 Two Pointers
0876 Middle of the Linked List Easy Two_Pointers, Linked_List 0 100.00
0019 Remove Nth Node From End of List Medium Top_100_Liked_Questions, Top_Interview_Questions, Two_Pointers, Linked_List, Big_O_Time_O(L)_Space_O(L) 0 100.00

Day 6 Sliding Window
0003 Longest Substring Without Repeating Characters Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n)_Space_O(1), AI_can_be_used_to_solve_the_task 2 98.59
0567 Permutation in String Medium Top_100_Liked_Questions, String, Hash_Table, Two_Pointers, Sliding_Window 5 93.93

Day 7 Breadth First Search Depth First Search
0733 Flood Fill Easy Array, Depth_First_Search, Breadth_First_Search, Matrix 1 85.36
0695 Max Area of Island Medium Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find 3 76.79

Day 8 Breadth First Search Depth First Search
0617 Merge Two Binary Trees Easy Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree 1 72.47
0116 Populating Next Right Pointers in Each Node Medium Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Linked_List 0 100.00

Day 9 Breadth First Search Depth First Search
0542 01 Matrix Medium Array, Dynamic_Programming, Breadth_First_Search, Matrix 7 95.83
0994 Rotting Oranges Medium Top_100_Liked_Questions, Array, Breadth_First_Search, Matrix 3 74.27

Day 10 Recursion Backtracking
0021 Merge Two Sorted Lists Easy Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n) 0 100.00
0206 Reverse Linked List Easy Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(N)_Space_O(1) 0 100.00

Day 11 Recursion Backtracking
0077 Combinations Medium Backtracking 11 77.40
0046 Permutations Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!) 1 94.08
0784 Letter Case Permutation Medium String, Bit_Manipulation, Backtracking 10 40.38

Day 12 Dynamic Programming
0070 Climbing Stairs Easy Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n) 0 100.00
0198 House Robber Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) 0 100.00
0120 Triangle Medium Array, Dynamic_Programming 2 94.63

Day 13 Bit Manipulation
0231 Power of Two Easy Math, Bit_Manipulation, Recursion 1 100.00
0191 Number of 1 Bits Easy Top_Interview_Questions, Bit_Manipulation 1 84.87

Day 14 Bit Manipulation
0190 Reverse Bits Easy Top_Interview_Questions, Bit_Manipulation, Divide_and_Conquer 1 98.66
0136 Single Number Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Big_O_Time_O(N)_Space_O(1) 1 99.86

Algorithm II

Day 1 Binary Search
0034 Find First and Last Position of Element in Sorted Array Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) 0 100.00
0033 Search in Rotated Sorted Array Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) 0 100.00
0074 Search a 2D Matrix Medium Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1) 0 100.00

Day 2 Binary Search
0153 Find Minimum in Rotated Sorted Array Medium Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_N)_Space_O(log_N) 0 100.00
0162 Find Peak Element Medium Top_Interview_Questions, Array, Binary_Search 0 100.00

Day 3 Two Pointers
0082 Remove Duplicates from Sorted List II Medium Two_Pointers, Linked_List 0 100.00
0015 3Sum Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n*log(n))_Space_O(n^2) 29 72.02

Day 4 Two Pointers
0844 Backspace String Compare Easy String, Two_Pointers, Stack, Simulation 0 100.00
0986 Interval List Intersections Medium Array, Two_Pointers 2 99.95
0011 Container With Most Water Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Greedy, Two_Pointers, Big_O_Time_O(n)_Space_O(1) 3 96.01

Day 5 Sliding Window
0438 Find All Anagrams in a String Medium Top_100_Liked_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n+m)_Space_O(1) 6 99.03
0713 Subarray Product Less Than K Medium Array, Sliding_Window 8 39.00
0209 Minimum Size Subarray Sum Medium Array, Binary_Search, Prefix_Sum, Sliding_Window 1 100.00

Day 6 Breadth First Search Depth First Search
0200 Number of Islands Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Big_O_Time_O(M*N)_Space_O(M*N) 3 87.24
0547 Number of Provinces Medium Depth_First_Search, Breadth_First_Search, Graph, Union_Find 2 69.51

Day 7 Breadth First Search Depth First Search
0117 Populating Next Right Pointers in Each Node II Medium Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Linked_List 0 100.00
0572 Subtree of Another Tree Easy Depth_First_Search, Tree, Binary_Tree, Hash_Function, String_Matching 2 97.06

Day 8 Breadth First Search Depth First Search
1091 Shortest Path in Binary Matrix Medium Array, Breadth_First_Search, Matrix 22 69.99
0130 Surrounded Regions Medium Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find 2 84.66
0797 All Paths From Source to Target Medium Depth_First_Search, Breadth_First_Search, Graph, Backtracking 2 90.53

Day 9 Recursion Backtracking
0078 Subsets Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Backtracking, Big_O_Time_O(2^n)_Space_O(n*2^n) 0 100.00
0090 Subsets II Medium Array, Bit_Manipulation, Backtracking 2 82.94

Day 10 Recursion Backtracking
0047 Permutations II Medium Array, Backtracking 1 99.86
0039 Combination Sum Medium Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n) 1 99.99
0040 Combination Sum II Medium Array, Backtracking 2 99.75

Day 11 Recursion Backtracking
0017 Letter Combinations of a Phone Number Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Backtracking, Big_O_Time_O(4^n)_Space_O(n) 0 100.00
0022 Generate Parentheses Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking, Big_O_Time_O(2^n)_Space_O(n) 0 100.00
0079 Word Search Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Backtracking, Big_O_Time_O(4^(m*n))_Space_O(m*n) 64 98.51

Day 12 Dynamic Programming
0213 House Robber II Medium Array, Dynamic_Programming 0 100.00
0055 Jump Game Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) 1 100.00

Day 13 Dynamic Programming
0045 Jump Game II Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) 0 100.00
0062 Unique Paths Medium Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(m*n)_Space_O(m*n) 0 100.00

Day 14 Dynamic Programming
0005 Longest Palindromic Substring Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) 7 97.82
0413 Arithmetic Slices Medium Array, Dynamic_Programming 0 100.00

Day 15 Dynamic Programming
0091 Decode Ways Medium Top_Interview_Questions, String, Dynamic_Programming 2 66.37
0139 Word Break Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Dynamic_Programming, Trie, Memoization, Big_O_Time_O(M+max*N)_Space_O(M+N+max) 1 99.42

Day 16 Dynamic Programming
0300 Longest Increasing Subsequence Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Binary_Search, Big_O_Time_O(n*log_n)_Space_O(n) 3 95.75
0673 Number of Longest Increasing Subsequence Medium Array, Dynamic_Programming, Segment_Tree, Binary_Indexed_Tree 25 68.75

Day 17 Dynamic Programming
1143 Longest Common Subsequence Medium Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n*m)_Space_O(n*m) 33 46.23
0583 Delete Operation for Two Strings Medium String, Dynamic_Programming 12 79.10

Day 18 Dynamic Programming
0072 Edit Distance Medium Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2) 3 97.19
0322 Coin Change Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Breadth_First_Search, Big_O_Time_O(m*n)_Space_O(amount) 12 92.59
0343 Integer Break Medium Dynamic_Programming, Math 0 100.00

Day 19 Bit Manipulation
0201 Bitwise AND of Numbers Range Medium Bit_Manipulation 8 74.15

Day 20 Others
0384 Shuffle an Array Medium Array, Math, Randomized 52 91.77

Day 21 Others
0202 Happy Number Easy Top_Interview_Questions, Hash_Table, Math, Two_Pointers 1 98.59
0149 Max Points on a Line Hard Top_Interview_Questions, Array, Hash_Table, Math, Geometry 11 99.21

Binary Search I

Day 1
0704 Binary Search Easy Top_100_Liked_Questions, Array, Binary_Search 0 100.00
0374 Guess Number Higher or Lower Easy Binary_Search, Interactive 0 100.00

Day 2
0035 Search Insert Position Easy Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) 0 100.00
0852 Peak Index in a Mountain Array Medium Array, Binary_Search 0 100.00

Day 3
0367 Valid Perfect Square Easy Math, Binary_Search 0 100.00
1385 Find the Distance Value Between Two Arrays Easy Array, Sorting, Binary_Search, Two_Pointers 5 65.78

Day 4
0069 Sqrt(x) Easy Top_Interview_Questions, Math, Binary_Search 1 99.51
0744 Find Smallest Letter Greater Than Target Easy Array, Binary_Search 0 100.00

Day 5
0278 First Bad Version Easy Binary_Search, Interactive 15 87.89
0034 Find First and Last Position of Element in Sorted Array Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) 0 100.00

Day 6
0441 Arranging Coins Easy Math, Binary_Search 2 95.97
1539 Kth Missing Positive Number Easy Array, Binary_Search 0 100.00

Day 7
0167 Two Sum II - Input Array Is Sorted Medium Array, Binary_Search, Two_Pointers 1 99.21
1608 Special Array With X Elements Greater Than or Equal X Easy Array, Sorting, Binary_Search 2 61.14

Day 8
1351 Count Negative Numbers in a Sorted Matrix Easy Array, Binary_Search, Matrix 1 49.66
0074 Search a 2D Matrix Medium Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1) 0 100.00

Day 9
1337 The K Weakest Rows in a Matrix Easy Array, Sorting, Binary_Search, Matrix, Heap_Priority_Queue 1 99.77
1346 Check If N and Its Double Exist Easy Array, Hash_Table, Sorting, Binary_Search, Two_Pointers 1 99.64

Day 10
0350 Intersection of Two Arrays II Easy Array, Hash_Table, Sorting, Binary_Search, Two_Pointers 4 69.62
0633 Sum of Square Numbers Medium Math, Binary_Search, Two_Pointers 4 82.92

Day 11
1855 Maximum Distance Between a Pair of Values Medium Array, Greedy, Binary_Search, Two_Pointers 4 62.20
0033 Search in Rotated Sorted Array Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) 0 100.00

Day 12
0153 Find Minimum in Rotated Sorted Array Medium Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_N)_Space_O(log_N) 0 100.00

Binary Search II

Day 1
0209 Minimum Size Subarray Sum Medium Array, Binary_Search, Prefix_Sum, Sliding_Window 1 100.00
0611 Valid Triangle Number Medium Array, Sorting, Greedy, Binary_Search, Two_Pointers 10 100.00

Day 2
0658 Find K Closest Elements Medium Array, Sorting, Binary_Search, Two_Pointers, Heap_Priority_Queue 3 99.20
1894 Find the Student that Will Replace the Chalk Medium Array, Binary_Search, Simulation, Prefix_Sum 2 76.67

Day 3
0300 Longest Increasing Subsequence Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Binary_Search, Big_O_Time_O(n*log_n)_Space_O(n) 3 95.75
1760 Minimum Limit of Balls in a Bag Medium Array, Binary_Search 44 78.49

Day 4
0875 Koko Eating Bananas Medium Array, Binary_Search 15 91.32
1552 Magnetic Force Between Two Balls Medium Array, Sorting, Binary_Search 39 99.65

Day 5
0287 Find the Duplicate Number Medium Top_100_Liked_Questions, Array, Binary_Search, Two_Pointers, Bit_Manipulation, Big_O_Time_O(n)_Space_O(n) 2 97.52
1283 Find the Smallest Divisor Given a Threshold Medium Array, Binary_Search 9 95.49

Day 6
1898 Maximum Number of Removable Characters Medium Array, String, Binary_Search 121 72.51
1870 Minimum Speed to Arrive on Time Medium Array, Binary_Search 86 88.58

Day 7
1482 Minimum Number of Days to Make m Bouquets Medium Array, Binary_Search 25 69.18
1818 Minimum Absolute Sum Difference Medium Array, Sorting, Binary_Search, Ordered_Set 13 99.44

Day 8
0240 Search a 2D Matrix II Medium Top_100_Liked_Questions, Array, Binary_Search, Matrix, Divide_and_Conquer, Big_O_Time_O(n+m)_Space_O(1) 5 99.92
0275 H-Index II Medium Array, Binary_Search 0 100.00

Day 9
1838 Frequency of the Most Frequent Element Medium Array, Sorting, Greedy, Binary_Search, Prefix_Sum, Sliding_Window 11 100.00
0540 Single Element in a Sorted Array Medium Array, Binary_Search 0 100.00

Day 10
0222 Count Complete Tree Nodes Easy Depth_First_Search, Tree, Binary_Search, Binary_Tree 0 100.00
1712 Ways to Split Array Into Three Subarrays Medium Array, Binary_Search, Two_Pointers, Prefix_Sum 16 84.24

Day 11
0826 Most Profit Assigning Work Medium Array, Sorting, Greedy, Binary_Search, Two_Pointers 21 83.83
0436 Find Right Interval Medium Array, Sorting, Binary_Search 20 81.51

Day 12
0081 Search in Rotated Sorted Array II Medium Array, Binary_Search 1 82.83
0162 Find Peak Element Medium Top_Interview_Questions, Array, Binary_Search 0 100.00

Day 13
0154 Find Minimum in Rotated Sorted Array II Hard Array, Binary_Search 1 77.09
0528 Random Pick with Weight Medium Math, Binary_Search, Prefix_Sum, Randomized 42 50.90

Day 14
1508 Range Sum of Sorted Subarray Sums Medium Array, Sorting, Binary_Search, Two_Pointers 60 93.84
1574 Shortest Subarray to be Removed to Make Array Sorted Medium Array, Binary_Search, Two_Pointers, Stack, Monotonic_Stack 2 84.97

Day 15
1292 Maximum Side Length of a Square with Sum Less than or Equal to Threshold Medium Array, Binary_Search, Matrix, Prefix_Sum 23 32.97
1498 Number of Subsequences That Satisfy the Given Sum Condition Medium Array, Sorting, Binary_Search, Two_Pointers 27 99.13

Day 16
0981 Time Based Key-Value Store Medium String, Hash_Table, Binary_Search, Design 239 72.78
1300 Sum of Mutated Array Closest to Target Medium Array, Sorting, Binary_Search 7 33.33

Day 17
1802 Maximum Value at a Given Index in a Bounded Array Medium Greedy, Binary_Search 2 58.44
1901 Find a Peak Element II Medium Array, Binary_Search, Matrix, Divide_and_Conquer 0 100.00

Day 18
1146 Snapshot Array Medium Array, Hash_Table, Binary_Search, Design 68 45.86
1488 Avoid Flood in The City Medium Array, Hash_Table, Greedy, Binary_Search, Heap_Priority_Queue 82 75.08

Day 19
1562 Find Latest Group of Size M Medium Array, Binary_Search, Simulation 8 90.00
1648 Sell Diminishing-Valued Colored Balls Medium Array, Math, Sorting, Greedy, Binary_Search, Heap_Priority_Queue 27 80.64

Day 20
1201 Ugly Number III Medium Math, Binary_Search, Number_Theory 0 100.00
0911 Online Election Medium Array, Hash_Table, Binary_Search, Design 63 98.81

Dynamic Programming I

Day 1
0509 Fibonacci Number Easy Dynamic_Programming, Math, Recursion, Memoization 0 100.00
1137 N-th Tribonacci Number Easy Dynamic_Programming, Math, Memoization 0 100.00

Day 2
0070 Climbing Stairs Easy Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n) 0 100.00
0746 Min Cost Climbing Stairs Easy Array, Dynamic_Programming 1 86.38

Day 3
0198 House Robber Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) 0 100.00
0213 House Robber II Medium Array, Dynamic_Programming 0 100.00
0740 Delete and Earn Medium Array, Hash_Table, Dynamic_Programming 4 77.68

Day 4
0055 Jump Game Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) 1 100.00
0045 Jump Game II Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) 0 100.00

Day 5
0053 Maximum Subarray Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1) 1 99.32
0918 Maximum Sum Circular Subarray Medium Array, Dynamic_Programming, Divide_and_Conquer, Queue, Monotonic_Queue 3 92.86

Day 6
0152 Maximum Product Subarray Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1) 1 92.74
1567 Maximum Length of Subarray With Positive Product Medium Array, Dynamic_Programming, Greedy 4 80.86

Day 7
1014 Best Sightseeing Pair Medium Array, Dynamic_Programming 2 99.86
0121 Best Time to Buy and Sell Stock Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1) 1 99.78
0122 Best Time to Buy and Sell Stock II Medium Top_Interview_Questions, Array, Dynamic_Programming, Greedy 1 96.82

Day 8
0309 Best Time to Buy and Sell Stock with Cooldown Medium Array, Dynamic_Programming 0 100.00
0714 Best Time to Buy and Sell Stock with Transaction Fee Medium Array, Dynamic_Programming, Greedy 4 78.57

Day 9
0139 Word Break Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Dynamic_Programming, Trie, Memoization, Big_O_Time_O(M+max*N)_Space_O(M+N+max) 1 99.42
0042 Trapping Rain Water Hard Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Two_Pointers, Stack, Monotonic_Stack, Big_O_Time_O(n)_Space_O(1) 0 100.00

Day 10
0413 Arithmetic Slices Medium Array, Dynamic_Programming 0 100.00
0091 Decode Ways Medium Top_Interview_Questions, String, Dynamic_Programming 2 66.37

Day 11
0264 Ugly Number II Medium Hash_Table, Dynamic_Programming, Math, Heap_Priority_Queue 2 99.91
0096 Unique Binary Search Trees Medium Dynamic_Programming, Math, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(n)_Space_O(1) 0 100.00

Day 12
0118 Pascal's Triangle Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming 1 67.08
0119 Pascal's Triangle II Easy Array, Dynamic_Programming 0 100.00

Day 13
0931 Minimum Falling Path Sum Medium Array, Dynamic_Programming, Matrix 4 72.19
0120 Triangle Medium Array, Dynamic_Programming 2 94.63

Day 14
1314 Matrix Block Sum Medium Array, Matrix, Prefix_Sum 5 67.46
0304 Range Sum Query 2D - Immutable Medium Array, Matrix, Design, Prefix_Sum 153 87.51

Day 15
0062 Unique Paths Medium Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(m*n)_Space_O(m*n) 0 100.00
0063 Unique Paths II Medium Array, Dynamic_Programming, Matrix 0 100.00

Day 16
0064 Minimum Path Sum Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Matrix, Big_O_Time_O(m*n)_Space_O(m*n) 1 99.73
0221 Maximal Square Medium Array, Dynamic_Programming, Matrix, Big_O_Time_O(m*n)_Space_O(m*n) 6 97.07

Day 17
0005 Longest Palindromic Substring Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) 7 97.82
0516 Longest Palindromic Subsequence Medium String, Dynamic_Programming 88 58.87

Day 18
0300 Longest Increasing Subsequence Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Binary_Search, Big_O_Time_O(n*log_n)_Space_O(n) 3 95.75
0376 Wiggle Subsequence Medium Array, Dynamic_Programming, Greedy 0 100.00

Day 19
0392 Is Subsequence Easy String, Dynamic_Programming, Two_Pointers 1 93.01
1143 Longest Common Subsequence Medium Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n*m)_Space_O(n*m) 33 46.23
0072 Edit Distance Medium Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2) 3 97.19

Day 20
0322 Coin Change Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Breadth_First_Search, Big_O_Time_O(m*n)_Space_O(amount) 12 92.59
0518 Coin Change 2 Medium Array, Dynamic_Programming 4 84.67

Day 21
0377 Combination Sum IV Medium Array, Dynamic_Programming 1 92.54
0343 Integer Break Medium Dynamic_Programming, Math 0 100.00
0279 Perfect Squares Medium Dynamic_Programming, Math, Breadth_First_Search 1 100.00

Programming Skills I

Day 1 Basic Data Type
1523 Count Odd Numbers in an Interval Range Easy Math 0 100.00
1491 Average Salary Excluding the Minimum and Maximum Salary Easy Array, Sorting 0 100.00

Day 2 Operator
0191 Number of 1 Bits Easy Top_Interview_Questions, Bit_Manipulation 1 84.87
1281 Subtract the Product and Sum of Digits of an Integer Easy Math 0 100.00

Day 3 Conditional Statements
0976 Largest Perimeter Triangle Easy Array, Math, Sorting, Greedy 12 26.01
1779 Find Nearest Point That Has the Same X or Y Coordinate Easy Array 1 100.00

Day 4 Loop
1822 Sign of the Product of an Array Easy Array, Math 1 58.05
1502 Can Make Arithmetic Progression From Sequence Easy Array, Sorting 2 90.55
0202 Happy Number Easy Top_Interview_Questions, Hash_Table, Math, Two_Pointers 1 98.59
1790 Check if One String Swap Can Make Strings Equal Easy String, Hash_Table, Counting 0 100.00

Day 5 Function
0589 N-ary Tree Preorder Traversal Easy Depth_First_Search, Tree, Stack 1 90.98
0496 Next Greater Element I Easy Array, Hash_Table, Stack, Monotonic_Stack 4 81.18
1232 Check If It Is a Straight Line Easy Array, Math, Geometry 0 100.00

Day 6 Array
1588 Sum of All Odd Length Subarrays Easy Array, Math, Prefix_Sum 0 100.00
0283 Move Zeroes Easy Top_100_Liked_Questions, Array, Two_Pointers, Big_O_Time_O(n)_Space_O(1) 2 83.99
1672 Richest Customer Wealth Easy Array, Matrix 0 100.00

Day 7 Array
1572 Matrix Diagonal Sum Easy Array, Matrix 0 100.00
0566 Reshape the Matrix Easy Array, Matrix, Simulation 1 90.08

Day 8 String
1768 Merge Strings Alternately Easy String, Two_Pointers 1 86.26
1678 Goal Parser Interpretation Easy String 0 100.00
0389 Find the Difference Easy String, Hash_Table, Sorting, Bit_Manipulation 1 100.00

Day 9 String
0709 To Lower Case Easy String 1 71.74
1309 Decrypt String from Alphabet to Integer Mapping Easy String 6 28.25
0953 Verifying an Alien Dictionary Easy Array, String, Hash_Table 0 100.00

Day 10 Linked List and Tree
1290 Convert Binary Number in a Linked List to Integer Easy Math, Linked_List 0 100.00
0876 Middle of the Linked List Easy Two_Pointers, Linked_List 0 100.00
0104 Maximum Depth of Binary Tree Easy Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(H) 0 100.00
0404 Sum of Left Leaves Easy Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree 1 29.26

Day 11 Containers and Libraries
1356 Sort Integers by The Number of 1 Bits Easy Array, Sorting, Bit_Manipulation, Counting 10 65.50
0232 Implement Queue using Stacks Easy Stack, Design, Queue 1 67.21
0242 Valid Anagram Easy String, Hash_Table, Sorting 2 99.01
0217 Contains Duplicate Easy Top_Interview_Questions, Array, Hash_Table, Sorting 6 96.68

Day 12 Class and Object
1603 Design Parking System Easy Design, Simulation, Counting 8 76.16
0303 Range Sum Query - Immutable Easy Array, Design, Prefix_Sum 7 100.00

Programming Skills II

Day 1
0896 Monotonic Array Easy Array 2 86.21
0028 Implement strStr() Easy Top_Interview_Questions, String, Two_Pointers, String_Matching 0 100.00

Day 2
0110 Balanced Binary Tree Easy Depth_First_Search, Tree, Binary_Tree 1 98.82
0459 Repeated Substring Pattern Easy String, String_Matching 8 96.64

Day 3
0150 Evaluate Reverse Polish Notation Medium Top_Interview_Questions, Array, Math, Stack 9 51.23
0066 Plus One Easy Top_Interview_Questions, Array, Math 0 100.00

Day 4
1367 Linked List in Binary Tree Medium Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Linked_List 2 61.23
0043 Multiply Strings Medium String, Math, Simulation 1 100.00

Day 5
0067 Add Binary Easy String, Math, Bit_Manipulation, Simulation 1 100.00
0989 Add to Array-Form of Integer Easy Array, Math 7 65.92

Day 6
0739 Daily Temperatures Medium Top_100_Liked_Questions, Array, Stack, Monotonic_Stack, Big_O_Time_O(n)_Space_O(n) 10 94.99
0058 Length of Last Word Easy String 0 100.00

Day 7
0048 Rotate Image Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Big_O_Time_O(n^2)_Space_O(1) 0 100.00
1886 Determine Whether Matrix Can Be Obtained By Rotation Easy Array, Matrix 1 78.38

Day 8
0054 Spiral Matrix Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Simulation 0 100.00
0973 K Closest Points to Origin Medium Array, Math, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Geometry, Quickselect 4 98.26

Day 9
1630 Arithmetic Subarrays Medium Array, Sorting 8 93.62
0429 N-ary Tree Level Order Traversal Medium Breadth_First_Search, Tree 3 80.26

Day 10
0503 Next Greater Element II Medium Array, Stack, Monotonic_Stack 7 97.03
0556 Next Greater Element III Medium String, Math, Two_Pointers 0 100.00

Day 11
1376 Time Needed to Inform All Employees Medium Depth_First_Search, Breadth_First_Search, Tree 8 99.85
0049 Group Anagrams Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, String, Hash_Table, Sorting, Big_O_Time_O(n*k_log_k)_Space_O(n) 6 97.61

Day 12
0438 Find All Anagrams in a String Medium Top_100_Liked_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n+m)_Space_O(1) 6 99.03
0713 Subarray Product Less Than K Medium Array, Sliding_Window 8 39.00

Day 13
0304 Range Sum Query 2D - Immutable Medium Array, Matrix, Design, Prefix_Sum 153 87.51
0910 Smallest Range II Medium Array, Math, Sorting, Greedy 10 73.16

Day 14
0143 Reorder List Medium Two_Pointers, Stack, Linked_List, Recursion 2 72.59
0138 Copy List with Random Pointer Medium Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Linked_List, Big_O_Time_O(N)_Space_O(N) 0 100.00

Day 15
0002 Add Two Numbers Medium Top_100_Liked_Questions, Top_Interview_Questions, Math, Linked_List, Recursion, Big_O_Time_O(max(N,M))_Space_O(max(N,M)), AI_can_be_used_to_solve_the_task 1 100.00
0445 Add Two Numbers II Medium Math, Stack, Linked_List 3 90.38

Day 16
0061 Rotate List Medium Two_Pointers, Linked_List 0 100.00
0173 Binary Search Tree Iterator Medium Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator 18 84.18

Day 17
1845 Seat Reservation Manager Medium Design, Heap_Priority_Queue 47 87.63
0860 Lemonade Change Easy Array, Greedy 2 90.84

Day 18
0155 Min Stack Medium Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Big_O_Time_O(1)_Space_O(N) 4 96.54
0341 Flatten Nested List Iterator Medium Depth_First_Search, Tree, Stack, Design, Queue, Iterator 2 99.95

Day 19
1797 Design Authentication Manager Medium Hash_Table, Design 41 92.67
0707 Design Linked List Medium Design, Linked_List 10 70.60

Day 20
0380 Insert Delete GetRandom O(1) Medium Array, Hash_Table, Math, Design, Randomized 27 93.44
0622 Design Circular Queue Medium Array, Design, Linked_List, Queue 3 100.00
0729 My Calendar I Medium Binary_Search, Design, Ordered_Set, Segment_Tree 17 97.23

Graph Theory I

Day 1 Matrix Related Problems
0733 Flood Fill Easy Array, Depth_First_Search, Breadth_First_Search, Matrix 1 85.36
0200 Number of Islands Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Big_O_Time_O(M*N)_Space_O(M*N) 3 87.24

Day 2 Matrix Related Problems
0695 Max Area of Island Medium Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find 3 76.79
1254 Number of Closed Islands Medium Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find 3 55.59

Day 3 Matrix Related Problems
1020 Number of Enclaves Medium Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find 6 68.24
1905 Count Sub Islands Medium Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find 24 85.54

Day 4 Matrix Related Problems
1162 As Far from Land as Possible Medium Array, Dynamic_Programming, Breadth_First_Search, Matrix 16 62.40
0417 Pacific Atlantic Water Flow Medium Array, Depth_First_Search, Breadth_First_Search, Matrix 5 92.62

Day 5 Matrix Related Problems
1091 Shortest Path in Binary Matrix Medium Array, Breadth_First_Search, Matrix 22 69.99
0542 01 Matrix Medium Array, Dynamic_Programming, Breadth_First_Search, Matrix 7 95.83

Day 6 Matrix Related Problems
0934 Shortest Bridge Medium Array, Depth_First_Search, Breadth_First_Search, Matrix 6 97.87
1926 Nearest Exit from Entrance in Maze Medium Array, Breadth_First_Search, Matrix 12 40.55

Day 7 Standard Traversal
0797 All Paths From Source to Target Medium Depth_First_Search, Breadth_First_Search, Graph, Backtracking 2 90.53
0841 Keys and Rooms Medium Depth_First_Search, Breadth_First_Search, Graph 3 51.54

Day 8 Standard Traversal
0547 Number of Provinces Medium Depth_First_Search, Breadth_First_Search, Graph, Union_Find 2 69.51
1319 Number of Operations to Make Network Connected Medium Depth_First_Search, Breadth_First_Search, Graph, Union_Find 9 67.64

Day 9 Standard Traversal
1376 Time Needed to Inform All Employees Medium Depth_First_Search, Breadth_First_Search, Tree 8 99.85
0802 Find Eventual Safe States Medium Depth_First_Search, Breadth_First_Search, Graph, Topological_Sort 7 74.93

Day 10 Standard Traversal
1129 Shortest Path with Alternating Colors Medium Breadth_First_Search, Graph 4 96.63
1466 Reorder Routes to Make All Paths Lead to the City Zero Medium Depth_First_Search, Breadth_First_Search, Graph 39 97.71
0847 Shortest Path Visiting All Nodes Hard Dynamic_Programming, Breadth_First_Search, Bit_Manipulation, Graph, Bitmask 14 78.72

Day 11 Breadth First Search
1306 Jump Game III Medium Array, Depth_First_Search, Breadth_First_Search 2 96.23
1654 Minimum Jumps to Reach Home Medium Array, Dynamic_Programming, Breadth_First_Search 6 99.87
0365 Water and Jug Problem Medium Math, Depth_First_Search, Breadth_First_Search 0 100.00

Day 12 Breadth First Search
0433 Minimum Genetic Mutation Medium String, Hash_Table, Breadth_First_Search 1 90.95
0752 Open the Lock Medium Array, String, Hash_Table, Breadth_First_Search 72 91.06
0127 Word Ladder Hard Top_Interview_Questions, String, Hash_Table, Breadth_First_Search 37 94.58

Day 13 Graph Theory
0997 Find the Town Judge Easy Array, Hash_Table, Graph 3 80.64
1557 Minimum Number of Vertices to Reach All Nodes Medium Graph 8 99.94

Day 14 Graph Theory
1615 Maximal Network Rank Medium Graph 3 97.34
0886 Possible Bipartition Medium Depth_First_Search, Breadth_First_Search, Graph, Union_Find 20 80.12
0785 Is Graph Bipartite? Medium Depth_First_Search, Breadth_First_Search, Graph, Union_Find 0 100.00

SQL I

Day 1 Select
0595 Big Countries Easy Database 262 84.64
1757 Recyclable and Low Fat Products Easy Database 475 71.54
0584 Find Customer Referee Easy Database 531 58.63
0183 Customers Who Never Order Easy Database 376 98.73

Day 2 Select and Order
1873 Calculate Special Bonus Easy Database 543 71.60
0627 Swap Salary Easy Database 191 96.89
0196 Delete Duplicate Emails Easy Database 903 48.10

Day 3 String Processing Functions
1667 Fix Names in a Table Easy Database 559 80.29
1484 Group Sold Products By The Date Easy LeetCode_Curated_SQL_70, Database 395 77.20
1527 Patients With a Condition Easy Database 308 66.93

Day 4 Union and Select
1965 Employees With Missing Information Easy Database 617 30.40
1795 Rearrange Products Table Easy Database 497 64.83
0608 Tree Node Medium LeetCode_Curated_SQL_70, Database 347 95.17
0176 Second Highest Salary Medium Database 225 73.10

Day 5 Union
0175 Combine Two Tables Easy Database 491 32.30
1581 Customer Who Visited but Did Not Make Any Transactions Easy Database 1039 76.99
1148 Article Views I Easy LeetCode_Curated_SQL_70, Database 783 64.09

Day 6 Union
0197 Rising Temperature Easy Database 342 93.76
0607 Sales Person Easy LeetCode_Curated_SQL_70, Database 1046 86.04

Day 7 Function
1141 User Activity for the Past 30 Days I Easy LeetCode_Curated_SQL_70, Database 849 72.54
1693 Daily Leads and Partners Easy Database 463 78.98
1729 Find Followers Count Easy Database 456 88.39

Day 8 Function
0586 Customer Placing the Largest Number of Orders Easy LeetCode_Curated_SQL_70, Database 484 66.42
0511 Game Play Analysis I Easy LeetCode_Curated_SQL_70, Database 586 56.94
1890 The Latest Login in 2020 Easy Database 571 73.59
1741 Find Total Time Spent by Each Employee Easy Database 414 93.27

Day 9 Control of Flow
1393 Capital Gain/Loss Medium LeetCode_Curated_SQL_70, Database 428 92.01
1407 Top Travellers Easy LeetCode_Curated_SQL_70, Database 682 70.16
1158 Market Analysis I Medium Database 2511 78.92

Day 10 Where
0182 Duplicate Emails Easy Database 303 92.08
1050 Actors and Directors Who Cooperated At Least Three Times Easy LeetCode_Curated_SQL_70, Database 344 76.48
1587 Bank Account Summary II Easy Database 630 60.32
1084 Sales Analysis III Easy LeetCode_Curated_SQL_70, Database 1066 69.71

Level 1

Day 1 Prefix Sum
1480 Running Sum of 1d Array Easy Array, Prefix_Sum 0 100.00
0724 Find Pivot Index Easy Array, Prefix_Sum 2 69.67

Day 2 String
0205 Isomorphic Strings Easy String, Hash_Table 2 99.97
0392 Is Subsequence Easy String, Dynamic_Programming, Two_Pointers 1 93.01

Day 3 Linked List
0021 Merge Two Sorted Lists Easy Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n) 0 100.00
0206 Reverse Linked List Easy Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(N)_Space_O(1) 0 100.00

Day 4 Linked List
0876 Middle of the Linked List Easy Two_Pointers, Linked_List 0 100.00
0142 Linked List Cycle II Medium Top_100_Liked_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1) 0 100.00

Day 5 Greedy
0121 Best Time to Buy and Sell Stock Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1) 1 99.78
0409 Longest Palindrome Easy String, Hash_Table, Greedy 2 92.90

Day 6 Tree
0589 N-ary Tree Preorder Traversal Easy Depth_First_Search, Tree, Stack 1 90.98
0102 Binary Tree Level Order Traversal Medium Top_100_Liked_Questions, Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N) 1 91.19

Day 7 Binary Search
0704 Binary Search Easy Top_100_Liked_Questions, Array, Binary_Search 0 100.00
0278 First Bad Version Easy Binary_Search, Interactive 15 87.89

Day 8 Binary Search Tree
0098 Validate Binary Search Tree Medium Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(N)_Space_O(log(N)) 0 100.00
0235 Lowest Common Ancestor of a Binary Search Tree Medium Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree 4 100.00

Day 9 Graph/BFS/DFS
0733 Flood Fill Easy Array, Depth_First_Search, Breadth_First_Search, Matrix 1 85.36
0200 Number of Islands Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Big_O_Time_O(M*N)_Space_O(M*N) 3 87.24

Day 10 Dynamic Programming
0509 Fibonacci Number Easy Dynamic_Programming, Math, Recursion, Memoization 0 100.00
0070 Climbing Stairs Easy Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n) 0 100.00

Day 11 Dynamic Programming
0746 Min Cost Climbing Stairs Easy Array, Dynamic_Programming 1 86.38
0062 Unique Paths Medium Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Combinatorics, Big_O_Time_O(m*n)_Space_O(m*n) 0 100.00

Day 12 Sliding Window/Two Pointer
0438 Find All Anagrams in a String Medium Top_100_Liked_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n+m)_Space_O(1) 6 99.03
0424 Longest Repeating Character Replacement Medium String, Hash_Table, Sliding_Window 5 95.15

Day 13 Hashmap
0001 Two Sum Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n), AI_can_be_used_to_solve_the_task 2 98.90
0299 Bulls and Cows Medium String, Hash_Table, Counting 6 86.69

Day 14 Stack
0844 Backspace String Compare Easy String, Two_Pointers, Stack, Simulation 0 100.00
0394 Decode String Medium Top_100_Liked_Questions, String, Stack, Recursion, Big_O_Time_O(n)_Space_O(n) 1 87.68

Day 15 Heap
1046 Last Stone Weight Easy Array, Heap_Priority_Queue 2 73.81
0692 Top K Frequent Words Medium String, Hash_Table, Sorting, Heap_Priority_Queue, Counting, Trie, Bucket_Sort 11 38.54

Level 2

Day 1 Implementation/Simulation
0202 Happy Number Easy Top_Interview_Questions, Hash_Table, Math, Two_Pointers 1 98.59
0054 Spiral Matrix Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Simulation 0 100.00
1706 Where Will the Ball Fall Medium Array, Dynamic_Programming, Depth_First_Search, Matrix, Simulation 2 64.55

Day 2 String
0014 Longest Common Prefix Easy Top_100_Liked_Questions, Top_Interview_Questions, String 0 100.00
0043 Multiply Strings Medium String, Math, Simulation 1 100.00

Day 3 Linked List
0019 Remove Nth Node From End of List Medium Top_100_Liked_Questions, Top_Interview_Questions, Two_Pointers, Linked_List, Big_O_Time_O(L)_Space_O(L) 0 100.00
0234 Palindrome Linked List Easy Top_100_Liked_Questions, Two_Pointers, Stack, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1) 4 84.46

Day 4 Linked List
0328 Odd Even Linked List Medium Linked_List 0 100.00
0148 Sort List Medium Top_100_Liked_Questions, Top_Interview_Questions, Sorting, Two_Pointers, Linked_List, Divide_and_Conquer, Merge_Sort, Big_O_Time_O(log(N))_Space_O(log(N)) 9 93.90

Day 5 Greedy
2131 Longest Palindrome by Concatenating Two Letter Words Medium Array, String, Hash_Table, Greedy, Counting 73 76.60
0621 Task Scheduler Medium Array, Hash_Table, Sorting, Greedy, Heap_Priority_Queue, Counting 3 84.32

Day 6 Tree
0226 Invert Binary Tree Easy Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n) 0 100.00
0110 Balanced Binary Tree Easy Depth_First_Search, Tree, Binary_Tree 1 98.82

Day 7 Tree
0543 Diameter of Binary Tree Easy Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n) 1 65.86
0437 Path Sum III Medium Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n) 18 45.66

Day 8 Binary Search
0074 Search a 2D Matrix Medium Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1) 0 100.00
0033 Search in Rotated Sorted Array Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) 0 100.00

Day 9 Binary Search Tree
0108 Convert Sorted Array to Binary Search Tree Easy Top_Interview_Questions, Array, Tree, Binary_Tree, Binary_Search_Tree, Divide_and_Conquer 0 100.00
0230 Kth Smallest Element in a BST Medium Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(n)_Space_O(n) 0 100.00
0173 Binary Search Tree Iterator Medium Tree, Binary_Tree, Stack, Design, Binary_Search_Tree, Iterator 18 84.18

Day 10 Graph/BFS/DFS
0994 Rotting Oranges Medium Top_100_Liked_Questions, Array, Breadth_First_Search, Matrix 3 74.27
0417 Pacific Atlantic Water Flow Medium Array, Depth_First_Search, Breadth_First_Search, Matrix 5 92.62

Day 11 Graph/BFS/DFS
0210 Course Schedule II Medium Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Graph, Topological_Sort 13 35.17
0815 Bus Routes Hard Array, Hash_Table, Breadth_First_Search 49 89.11

Day 12 Dynamic Programming
0198 House Robber Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) 0 100.00
0322 Coin Change Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Breadth_First_Search, Big_O_Time_O(m*n)_Space_O(amount) 12 92.59

Day 13 Dynamic Programming
0416 Partition Equal Subset Sum Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Big_O_Time_O(n*sums)_Space_O(n*sums) 27 94.53
0152 Maximum Product Subarray Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1) 1 92.74

Day 14 Sliding Window/Two Pointer
0003 Longest Substring Without Repeating Characters Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n)_Space_O(1), AI_can_be_used_to_solve_the_task 2 98.59
0016 3Sum Closest Medium Array, Sorting, Two_Pointers 4 98.21
0076 Minimum Window Substring Hard Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(s.length())_Space_O(1) 2 99.83

Day 15 Tree
0100 Same Tree Easy Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree 0 100.00
0101 Symmetric Tree Easy Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(log(N)) 0 100.00
0199 Binary Tree Right Side View Medium Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree 1 94.57

Day 16 Design
0232 Implement Queue using Stacks Easy Stack, Design, Queue 1 67.21
0155 Min Stack Medium Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Big_O_Time_O(1)_Space_O(N) 4 96.54
0208 Implement Trie (Prefix Tree) Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Design, Trie, Big_O_Time_O(word.length())_or_O(prefix.length())_Space_O(N) 32 95.05

Day 17 Interval
0057 Insert Interval Medium Array 0 100.00
0056 Merge Intervals Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n) 7 98.37

Day 18 Stack
0735 Asteroid Collision Medium Array, Stack 2 99.59
0227 Basic Calculator II Medium String, Math, Stack 8 95.32

Day 19 Union Find
0547 Number of Provinces Medium Depth_First_Search, Breadth_First_Search, Graph, Union_Find 2 69.51
0947 Most Stones Removed with Same Row or Column Medium Depth_First_Search, Graph, Union_Find 7 98.83

Day 20 Brute Force/Backtracking
0039 Combination Sum Medium Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n) 1 99.99
0046 Permutations Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!) 1 94.08

Udemy

Udemy Integers
0412 Fizz Buzz Easy String, Math, Simulation 1 100.00
0136 Single Number Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Big_O_Time_O(N)_Space_O(1) 1 99.86
0007 Reverse Integer Medium Top_Interview_Questions, Math 0 100.00
0009 Palindrome Number Easy Math 4 100.00
0172 Factorial Trailing Zeroes Medium Top_Interview_Questions, Math 1 85.61
0050 Pow(x, n) Medium Top_Interview_Questions, Math, Recursion 0 100.00

Udemy Strings
0344 Reverse String Easy String, Two_Pointers, Recursion 1 99.91
0014 Longest Common Prefix Easy Top_100_Liked_Questions, Top_Interview_Questions, String 0 100.00
0187 Repeated DNA Sequences Medium String, Hash_Table, Bit_Manipulation, Sliding_Window, Hash_Function, Rolling_Hash 29 77.11
0003 Longest Substring Without Repeating Characters Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Sliding_Window, Big_O_Time_O(n)_Space_O(1), AI_can_be_used_to_solve_the_task 2 98.59
0020 Valid Parentheses Easy Top_100_Liked_Questions, Top_Interview_Questions, String, Stack, Big_O_Time_O(n)_Space_O(n) 2 97.19
0005 Longest Palindromic Substring Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) 7 97.82
0394 Decode String Medium Top_100_Liked_Questions, String, Stack, Recursion, Big_O_Time_O(n)_Space_O(n) 1 87.68
0242 Valid Anagram Easy String, Hash_Table, Sorting 2 99.01
0049 Group Anagrams Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, String, Hash_Table, Sorting, Big_O_Time_O(n*k_log_k)_Space_O(n) 6 97.61
0151 Reverse Words in a String Medium String, Two_Pointers 2 99.94
0273 Integer to English Words Hard String, Math, Recursion 3 95.67

Udemy Binary Search
0704 Binary Search Easy Top_100_Liked_Questions, Array, Binary_Search 0 100.00
0033 Search in Rotated Sorted Array Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Binary_Search, Big_O_Time_O(log_n)_Space_O(1) 0 100.00
0153 Find Minimum in Rotated Sorted Array Medium Top_100_Liked_Questions, Array, Binary_Search, Big_O_Time_O(log_N)_Space_O(log_N) 0 100.00

Udemy Arrays
0121 Best Time to Buy and Sell Stock Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1) 1 99.78
0283 Move Zeroes Easy Top_100_Liked_Questions, Array, Two_Pointers, Big_O_Time_O(n)_Space_O(1) 2 83.99
0001 Two Sum Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n), AI_can_be_used_to_solve_the_task 2 98.90
0217 Contains Duplicate Easy Top_Interview_Questions, Array, Hash_Table, Sorting 6 96.68
0058 Length of Last Word Easy String 0 100.00
0605 Can Place Flowers Easy Array, Greedy 1 96.77
0122 Best Time to Buy and Sell Stock II Medium Top_Interview_Questions, Array, Dynamic_Programming, Greedy 1 96.82
0080 Remove Duplicates from Sorted Array II Medium Array, Two_Pointers 0 100.00
0189 Rotate Array Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Two_Pointers, Big_O_Time_O(n)_Space_O(1) 0 100.00
0055 Jump Game Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Greedy, Big_O_Time_O(n)_Space_O(1) 1 100.00
0075 Sort Colors Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n)_Space_O(1) 0 100.00
0066 Plus One Easy Top_Interview_Questions, Array, Math 0 100.00
0238 Product of Array Except Self Medium Top_100_Liked_Questions, Array, Prefix_Sum, Big_O_Time_O(n^2)_Space_O(n) 1 99.66
1291 Sequential Digits Medium Enumeration 0 100.00
0448 Find All Numbers Disappeared in an Array Easy Array, Hash_Table 3 100.00
0442 Find All Duplicates in an Array Medium Array, Hash_Table 5 98.83
0041 First Missing Positive Hard Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n) 1 100.00
0697 Degree of an Array Easy Array, Hash_Table 14 93.19
0532 K-diff Pairs in an Array Medium Array, Hash_Table, Sorting, Binary_Search, Two_Pointers 13 58.23
0713 Subarray Product Less Than K Medium Array, Sliding_Window 8 39.00
1007 Minimum Domino Rotations For Equal Row Medium Array, Greedy 5 79.64
1306 Jump Game III Medium Array, Depth_First_Search, Breadth_First_Search 2 96.23
0456 132 Pattern Medium Array, Binary_Search, Stack, Ordered_Set, Monotonic_Stack 16 82.41
0239 Sliding Window Maximum Hard Top_100_Liked_Questions, Array, Heap_Priority_Queue, Sliding_Window, Queue, Monotonic_Queue, Big_O_Time_O(n*k)_Space_O(n+k) 26 95.89

Udemy Two Pointers
0392 Is Subsequence Easy String, Dynamic_Programming, Two_Pointers 1 93.01
0125 Valid Palindrome Easy Top_Interview_Questions, String, Two_Pointers 3 98.64
0977 Squares of a Sorted Array Easy Array, Sorting, Two_Pointers 1 100.00
0026 Remove Duplicates from Sorted Array Easy Top_Interview_Questions, Array, Two_Pointers 1 98.56
0042 Trapping Rain Water Hard Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Two_Pointers, Stack, Monotonic_Stack, Big_O_Time_O(n)_Space_O(1) 0 100.00
0015 3Sum Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Two_Pointers, Big_O_Time_O(n*log(n))_Space_O(n^2) 29 72.02

Udemy Famous Algorithm
0053 Maximum Subarray Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1) 1 99.32
0169 Majority Element Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Sorting, Counting, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1) 1 99.89

Udemy Sorting Algorithms
0912 Sort an Array Medium Array, Sorting, Heap_Priority_Queue, Divide_and_Conquer, Merge_Sort, Bucket_Sort, Counting_Sort, Radix_Sort 25 38.15

Udemy 2D Arrays/Matrix
0304 Range Sum Query 2D - Immutable Medium Array, Matrix, Design, Prefix_Sum 153 87.51
0074 Search a 2D Matrix Medium Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1) 0 100.00
0054 Spiral Matrix Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Matrix, Simulation 0 100.00
0048 Rotate Image Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Math, Matrix, Big_O_Time_O(n^2)_Space_O(1) 0 100.00
1572 Matrix Diagonal Sum Easy Array, Matrix 0 100.00
0073 Set Matrix Zeroes Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Matrix, Big_O_Time_O(m*n)_Space_O(1) 0 100.00
0056 Merge Intervals Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Sorting, Big_O_Time_O(n_log_n)_Space_O(n) 7 98.37

Udemy Linked List
0114 Flatten Binary Tree to Linked List Medium Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Linked_List, Big_O_Time_O(N)_Space_O(N) 0 100.00
0445 Add Two Numbers II Medium Math, Stack, Linked_List 3 90.38
0328 Odd Even Linked List Medium Linked_List 0 100.00
0061 Rotate List Medium Two_Pointers, Linked_List 0 100.00
0024 Swap Nodes in Pairs Medium Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1) 0 100.00
0876 Middle of the Linked List Easy Two_Pointers, Linked_List 0 100.00
0142 Linked List Cycle II Medium Top_100_Liked_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1) 0 100.00
0141 Linked List Cycle Easy Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1) 0 100.00
0206 Reverse Linked List Easy Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(N)_Space_O(1) 0 100.00
0021 Merge Two Sorted Lists Easy Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n) 0 100.00
0160 Intersection of Two Linked Lists Easy Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(M+N)_Space_O(1) 1 99.92
0234 Palindrome Linked List Easy Top_100_Liked_Questions, Two_Pointers, Stack, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(1) 4 84.46
0138 Copy List with Random Pointer Medium Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Linked_List, Big_O_Time_O(N)_Space_O(N) 0 100.00
0025 Reverse Nodes in k-Group Hard Top_100_Liked_Questions, Linked_List, Recursion, Big_O_Time_O(n)_Space_O(k) 0 100.00
0146 LRU Cache Medium Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Design, Linked_List, Doubly_Linked_List, Big_O_Time_O(1)_Space_O(capacity) 40 98.20
0707 Design Linked List Medium Design, Linked_List 10 70.60

Udemy Tree Stack Queue
0144 Binary Tree Preorder Traversal Easy Depth_First_Search, Tree, Binary_Tree, Stack 1 48.38
0094 Binary Tree Inorder Traversal Easy Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Big_O_Time_O(n)_Space_O(n) 0 100.00
0145 Binary Tree Postorder Traversal Easy Depth_First_Search, Tree, Binary_Tree, Stack 1 49.11
0102 Binary Tree Level Order Traversal Medium Top_100_Liked_Questions, Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N) 1 91.19
0103 Binary Tree Zigzag Level Order Traversal Medium Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree 1 95.00
0108 Convert Sorted Array to Binary Search Tree Easy Top_Interview_Questions, Array, Tree, Binary_Tree, Binary_Search_Tree, Divide_and_Conquer 0 100.00
1008 Construct Binary Search Tree from Preorder Traversal Medium Array, Tree, Binary_Tree, Stack, Monotonic_Stack, Binary_Search_Tree 0 100.00
0543 Diameter of Binary Tree Easy Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n) 1 65.86
0938 Range Sum of BST Easy Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree 0 100.00
0100 Same Tree Easy Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree 0 100.00
0226 Invert Binary Tree Easy Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n) 0 100.00
0111 Minimum Depth of Binary Tree Easy Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree 1 97.49
0104 Maximum Depth of Binary Tree Easy Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(H) 0 100.00
0110 Balanced Binary Tree Easy Depth_First_Search, Tree, Binary_Tree 1 98.82
0701 Insert into a Binary Search Tree Medium Tree, Binary_Tree, Binary_Search_Tree 0 100.00
0297 Serialize and Deserialize Binary Tree Hard String, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Design 7 98.13
0124 Binary Tree Maximum Path Sum Hard Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N) 0 100.00
0098 Validate Binary Search Tree Medium Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(N)_Space_O(log(N)) 0 100.00
0337 House Robber III Medium Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree 1 91.77
0236 Lowest Common Ancestor of a Binary Tree Medium Top_100_Liked_Questions, Depth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n) 6 100.00
0968 Binary Tree Cameras Hard Dynamic_Programming, Depth_First_Search, Tree, Binary_Tree 0 100.00

Udemy Trie and Heap
0208 Implement Trie (Prefix Tree) Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Design, Trie, Big_O_Time_O(word.length())_or_O(prefix.length())_Space_O(N) 32 95.05
0745 Prefix and Suffix Search Hard String, Design, Trie 366 76.15

Udemy Graph
0200 Number of Islands Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Depth_First_Search, Breadth_First_Search, Matrix, Union_Find, Big_O_Time_O(M*N)_Space_O(M*N) 3 87.24
0133 Clone Graph Medium Hash_Table, Depth_First_Search, Breadth_First_Search, Graph 45 29.80
0417 Pacific Atlantic Water Flow Medium Array, Depth_First_Search, Breadth_First_Search, Matrix 5 92.62

Udemy Dynamic Programming
0120 Triangle Medium Array, Dynamic_Programming 2 94.63
0118 Pascal's Triangle Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming 1 67.08
0119 Pascal's Triangle II Easy Array, Dynamic_Programming 0 100.00
0139 Word Break Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Dynamic_Programming, Trie, Memoization, Big_O_Time_O(M+max*N)_Space_O(M+N+max) 1 99.42
0152 Maximum Product Subarray Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1) 1 92.74
0198 House Robber Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(n)_Space_O(n) 0 100.00
0213 House Robber II Medium Array, Dynamic_Programming 0 100.00
0509 Fibonacci Number Easy Dynamic_Programming, Math, Recursion, Memoization 0 100.00
0070 Climbing Stairs Easy Top_100_Liked_Questions, Top_Interview_Questions, Dynamic_Programming, Math, Memoization, Big_O_Time_O(n)_Space_O(n) 0 100.00
0064 Minimum Path Sum Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Matrix, Big_O_Time_O(m*n)_Space_O(m*n) 1 99.73
0300 Longest Increasing Subsequence Medium Top_100_Liked_Questions, Array, Dynamic_Programming, Binary_Search, Big_O_Time_O(n*log_n)_Space_O(n) 3 95.75
1143 Longest Common Subsequence Medium Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n*m)_Space_O(n*m) 33 46.23
0072 Edit Distance Medium Top_100_Liked_Questions, String, Dynamic_Programming, Big_O_Time_O(n^2)_Space_O(n2) 3 97.19
0044 Wildcard Matching Hard Top_Interview_Questions, String, Dynamic_Programming, Greedy, Recursion 2 99.87
0010 Regular Expression Matching Hard Top_Interview_Questions, String, Dynamic_Programming, Recursion, Big_O_Time_O(m*n)_Space_O(m*n) 1 100.00

Udemy Backtracking/Recursion
0022 Generate Parentheses Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Dynamic_Programming, Backtracking, Big_O_Time_O(2^n)_Space_O(n) 0 100.00
0039 Combination Sum Medium Top_100_Liked_Questions, Array, Backtracking, Big_O_Time_O(2^n)_Space_O(n+2^n) 1 99.99
0216 Combination Sum III Medium Array, Backtracking 1 81.35
0078 Subsets Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Bit_Manipulation, Backtracking, Big_O_Time_O(2^n)_Space_O(n*2^n) 0 100.00
0017 Letter Combinations of a Phone Number Medium Top_100_Liked_Questions, Top_Interview_Questions, String, Hash_Table, Backtracking, Big_O_Time_O(4^n)_Space_O(n) 0 100.00
0046 Permutations Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Backtracking, Big_O_Time_O(n*n!)_Space_O(n+n!) 1 94.08

Udemy Bit Manipulation
0191 Number of 1 Bits Easy Top_Interview_Questions, Bit_Manipulation 1 84.87
0389 Find the Difference Easy String, Hash_Table, Sorting, Bit_Manipulation 1 100.00
0190 Reverse Bits Easy Top_Interview_Questions, Bit_Manipulation, Divide_and_Conquer 1 98.66
0461 Hamming Distance Easy Bit_Manipulation 0 100.00
1009 Complement of Base 10 Integer Easy Bit_Manipulation 1 41.56
0338 Counting Bits Easy Dynamic_Programming, Bit_Manipulation, Big_O_Time_O(num)_Space_O(num) 2 96.37
0371 Sum of Two Integers Medium Math, Bit_Manipulation 0 100.00
0029 Divide Two Integers Medium Top_Interview_Questions, Math, Bit_Manipulation 1 97.44

Udemy Design
0155 Min Stack Medium Top_100_Liked_Questions, Top_Interview_Questions, Stack, Design, Big_O_Time_O(1)_Space_O(N) 4 96.54

Data Structure I

Day 1 Array
0217 Contains Duplicate Easy Top_Interview_Questions, Array, Hash_Table, Sorting 6 96.68
0053 Maximum Subarray Medium Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Divide_and_Conquer, Big_O_Time_O(n)_Space_O(1) 1 99.32

Day 2 Array
0001 Two Sum Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Hash_Table, Big_O_Time_O(n)_Space_O(n), AI_can_be_used_to_solve_the_task 2 98.90
0088 Merge Sorted Array Easy Top_Interview_Questions, Array, Sorting, Two_Pointers 0 100.00

Day 3 Array
0350 Intersection of Two Arrays II Easy Array, Hash_Table, Sorting, Binary_Search, Two_Pointers 4 69.62
0121 Best Time to Buy and Sell Stock Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming, Big_O_Time_O(N)_Space_O(1) 1 99.78

Day 4 Array
0566 Reshape the Matrix Easy Array, Matrix, Simulation 1 90.08
0118 Pascal's Triangle Easy Top_100_Liked_Questions, Top_Interview_Questions, Array, Dynamic_Programming 1 67.08

Day 5 Array
0036 Valid Sudoku Medium Top_Interview_Questions, Array, Hash_Table, Matrix 1 100.00
0074 Search a 2D Matrix Medium Top_100_Liked_Questions, Array, Binary_Search, Matrix, Big_O_Time_O(endRow+endCol)_Space_O(1) 0 100.00

Day 6 String
0387 First Unique Character in a String Easy String, Hash_Table, Counting, Queue 1 100.00
0383 Ransom Note Easy String, Hash_Table, Counting 1 99.97
0242 Valid Anagram Easy String, Hash_Table, Sorting 2 99.01

Day 7 Linked List
0141 Linked List Cycle Easy Top_100_Liked_Questions, Top_Interview_Questions, Hash_Table, Two_Pointers, Linked_List, Big_O_Time_O(N)_Space_O(1) 0 100.00
0021 Merge Two Sorted Lists Easy Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(m+n)_Space_O(m+n) 0 100.00
0203 Remove Linked List Elements Easy Linked_List, Recursion 1 98.82

Day 8 Linked List
0206 Reverse Linked List Easy Top_100_Liked_Questions, Top_Interview_Questions, Linked_List, Recursion, Big_O_Time_O(N)_Space_O(1) 0 100.00
0083 Remove Duplicates from Sorted List Easy Linked_List 0 100.00

Day 9 Stack Queue
0020 Valid Parentheses Easy Top_100_Liked_Questions, Top_Interview_Questions, String, Stack, Big_O_Time_O(n)_Space_O(n) 2 97.19
0232 Implement Queue using Stacks Easy Stack, Design, Queue 1 67.21

Day 10 Tree
0144 Binary Tree Preorder Traversal Easy Depth_First_Search, Tree, Binary_Tree, Stack 1 48.38
0094 Binary Tree Inorder Traversal Easy Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Stack, Big_O_Time_O(n)_Space_O(n) 0 100.00
0145 Binary Tree Postorder Traversal Easy Depth_First_Search, Tree, Binary_Tree, Stack 1 49.11

Day 11 Tree
0102 Binary Tree Level Order Traversal Medium Top_100_Liked_Questions, Top_Interview_Questions, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(N) 1 91.19
0104 Maximum Depth of Binary Tree Easy Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(H) 0 100.00
0101 Symmetric Tree Easy Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(N)_Space_O(log(N)) 0 100.00

Day 12 Tree
0226 Invert Binary Tree Easy Top_100_Liked_Questions, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Big_O_Time_O(n)_Space_O(n) 0 100.00
0112 Path Sum Easy Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree 0 100.00

Day 13 Tree
0700 Search in a Binary Search Tree Easy Tree, Binary_Tree, Binary_Search_Tree 0 100.00
0701 Insert into a Binary Search Tree Medium Tree, Binary_Tree, Binary_Search_Tree 0 100.00

Day 14 Tree
0098 Validate Binary Search Tree Medium Top_100_Liked_Questions, Top_Interview_Questions, Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree, Big_O_Time_O(N)_Space_O(log(N)) 0 100.00
0653 Two Sum IV - Input is a BST Easy Hash_Table, Depth_First_Search, Breadth_First_Search, Tree, Binary_Tree, Two_Pointers, Binary_Search_Tree 5 74.23
0235 Lowest Common Ancestor of a Binary Search Tree Medium Depth_First_Search, Tree, Binary_Tree, Binary_Search_Tree 4 100.00

Contributing

Your ideas/fixes/algorithms are more than welcome!

  1. Fork this repo
  2. Clone your forked repo (git clone https://github.com/YOUR_GITHUB_USERNAME/LeetCode-in-Java.git) onto your local machine
  3. cd into your cloned directory, create your feature branch (git checkout -b my-awesome-fix)
  4. git add your desired changes to this repo
  5. Commit your changes (git commit -m 'Added some awesome features/fixes')
  6. Push to the branch (git push origin my-awesome-feature)
  7. Open your forked repo on Github website, create a new Pull Request to this repo!

About

Java-based LeetCode algorithm problem solutions, regularly updated.

leetcode-in-java.github.io

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java algorithm math leetcode algorithm-competitions leetcode-solutions interview-questions dynamic-programming leetcode-java algorithms-and-data-structures

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Version 1.37 Latest
Nov 1, 2024
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