90 Days of Code Challenge

This challenge is currently meant for the students of NIT Durgapur. Commit yourself to our 90 days of code challenge and contribute to the improvement of the coding culture of our college.

Starts from 28th February 2018

This challenge is going to help only if you solve the problems on your own, without cheating. Your main goal should be learning, not scoring.

Ranklist

before 26th March 2018

1. raghav7997 204 points (+58)
2. lostground97 193 points (+49)
3. Ruchi-nitd 118 points (+40)
4. ashutosh97 47 points (+47)
5. piyu007 43 points (+0)
6. deblina-talukdar 8 points (+0)
7. akjais99 8 points (+0)

Next ranklist with username and score will be updated here on 3rd April 2018.

Getting Started

If you’ve decided to join, following are the steps you need to go through:

1. From today onwards, for the next 90 days, you are going to commit to our 90 days of coding challenge.
2. You are expected to code each and every day and solve as many problems as you can.
3. You should solve problems on your own. Try for at least 4-5 hours, then you may seek help.
4. Solutions of almost all problems are available online. In case of further doubts, visit AskREC.
5. Create your own branch, solve the problems daily, mark the corresponding checkbox in this file in your corresponsing branch, commit and push to github.
6. Encourage at least 5 of your friends to do the same.
7. Raise an issue and/or a pull request if you want something to be improved and/or to add a question.

Steps to follow to push changes

1. fork this repo
2. clone your forked repo, not this repo.
3. create a new branch (branch name should be same as your username on github).
4. commit your changes on your branch, nothing on master branch.
5. push it to your forked repo.
6. Send a merge request

Do steps 1 to 3 once and then steps 4 to 6 daily to update the changes.

Prerequisites

• Basic git knowledge. You can learn it from here
• A working laptop and an internet connection.

Scoring

1. Each push is worth 3 points (Minimum 1 question should be solved) and every 5 continuous push will increase your score by 20 percent.

2. For each solved question, score is calculated as follows:

   • Easy section 5 points
   • Medium section 7 points
   • Hard section 10 points

3. At the end of every 10 days, we will update our ranklist. Following predefined score (F1 based) will be added to your total score based on your rank.
   25 - 18 - 15 - 12 - 10 - 8 - 6 - 4 - 2 - 1

Update this section at every push

X = data before current push
Y = data after current push

Change the following block only

Number of easy questions solved: X Y
Number of medium questions solved: X Y
Number of hard questions solved: X Y
Number of total questions solved: X Y

Change X and Y only according to your progress.**

For example - if you solved 1 easy question and 2 hard questions today
 	Number of easy questions solved: 0 1
	Number of medium questions solved: 0 0
	Number of hard questions solved: 0 2
	Number of total questions solved: 0 3

Please note that any misinformation will decrease your score by 100.

To mark the checkbox, change [ ] to [x].

Questions

Easy

1. https://goo.gl/Kkf8eD
2. https://www.codechef.com/problems/SCC0103
3. http://www.spoj.com/problems/GSS1/
4. https://www.codechef.com/problems/BITMASK3
5. https://goo.gl/PTpmny
6. https://www.codechef.com/problems/BITMASK3
7. https://www.hackerrank.com/challenges/two-arrays/problem
8. http://www.spoj.com/problems/FREQUENT/
9. http://www.spoj.com/problems/BUGLIFE/
10. https://goo.gl/shR8UK
11. http://www.spoj.com/problems/GERGOVIA/
12. http://codeforces.com/problemset/problem/793/C
13. http://www.spoj.com/problems/COINS/
14. https://goo.gl/h7a3mN
15. https://goo.gl/MDTg6s
16. http://www.spoj.com/problems/TOPOSORT/
17. https://www.hackerrank.com/challenges/angry-children/problem
18. http://www.spoj.com/problems/QUEEN/
19. http://www.spoj.com/problems/HORRIBLE/
20. http://www.spoj.com/problems/PAIRS1/
21. http://www.spoj.com/problems/JUSTAPAL/
22. https://goo.gl/m5DbXZ
23. http://www.spoj.com/problems/ELEVTRBL/
24. https://www.codechef.com/problems/K1/
25. http://www.spoj.com/problems/PT07Y/
26. https://goo.gl/JHSdm1
27. https://goo.gl/viMSCX
28. https://goo.gl/PzwksW
29. http://www.spoj.com/problems/BLHETA/
30. https://goo.gl/TGfXMv
31. https://www.hackerrank.com/challenges/angry-children/problem
32. https://www.codechef.com/problems/PANSTACK
33. https://goo.gl/1A7rHf
34. https://www.hackerrank.com/challenges/flipping-bits/problem
35. https://www.codechef.com/problems/CDX1604
36. https://goo.gl/u1ZFt7
37. http://www.spoj.com/problems/STRMATCH/
38. https://goo.gl/NnEu73
39. https://www.hackerrank.com/challenges/lonely-integer/problem
40. https://www.codechef.com/problems/FIRESC
41. http://codeforces.com/problemset/problem/579/A
42. https://goo.gl/66cr2p
43. https://goo.gl/fvbDS5
44. https://www.codechef.com/problems/REL102
45. http://www.spoj.com/problems/SUMITR/
46. https://goo.gl/S69rSA
47. https://goo.gl/xMWucx
48. http://www.spoj.com/problems/CRSCNTRY/
49. https://goo.gl/uH7FYz
50. https://goo.gl/DDzNyE
51. https://goo.gl/tSnDU7
52. https://www.hackerrank.com/challenges/sum-vs-xor/problem
53. http://www.spoj.com/problems/ADAJOBS/

Medium

1. http://www.spoj.com/problems/RENT/
2. https://www.codechef.com/DCL1501/problems/DCL2015E/ [2D BIT]
3. http://codeforces.com/problemset/problem/774/D
4. http://www.spoj.com/problems/KNAPSACK/
5. http://www.spoj.com/problems/GCPC11J/
6. https://goo.gl/yLirva
7. http://codeforces.com/problemset/problem/777/B
8. https://www.hackerrank.com/challenges/largest-permutation/problem
9. http://www.spoj.com/problems/CODESPTB/
10. https://www.codechef.com/problems/TRAL
11. http://www.spoj.com/problems/SDITSAVL/ [AVL tree]
12. http://codeforces.com/problemset/problem/439/D
13. http://www.spoj.com/problems/PPATH/
14. http://www.spoj.com/problems/DISUBSTR/ [suffix tree or suffix array]
15. https://goo.gl/jNsdWQ
16. https://www.hackerrank.com/challenges/morgan-and-a-string/problem
17. https://goo.gl/1tU579 [sqrt decompostion]
18. http://www.spoj.com/problems/PT07Z/
19. http://www.spoj.com/problems/ADABRANC/
20. https://www.hackerrank.com/challenges/richie-rich/problem
21. https://www.hackerrank.com/challenges/pylons/problem
22. http://www.spoj.com/problems/MAKETREE/
23. https://www.codechef.com/problems/RRDAG
24. http://www.spoj.com/problems/BUSYMAN/
25. http://codeforces.com/problemset/problem/579/A
26. http://codeforces.com/problemset/problem/106/E
27. http://www.spoj.com/problems/PARTIT/
28. http://codeforces.com/problemset/problem/431/E
29. http://codeforces.com/problemset/problem/898/C
30. https://www.codechef.com/problems/WTHINGS
31. http://www.spoj.com/problems/FACEFRND/
32. https://goo.gl/DWyiui [persistent segTree]
33. https://goo.gl/5MwpVj [trie]
34. http://www.spoj.com/problems/LABYR1/
35. https://www.codechef.com/problems/CROFT
36. https://www.hackerrank.com/challenges/aorb/problem
37. https://www.hackerrank.com/challenges/similar-strings/problem
38. http://codeforces.com/problemset/problem/633/C
39. https://goo.gl/GcBqqy
40. https://goo.gl/poJyjN
41. http://www.spoj.com/problems/DQUERY/
42. http://codeforces.com/problemset/problem/777/D
43. http://www.spoj.com/problems/MIXTURES/
44. https://www.hackerrank.com/challenges/whats-next/problem
45. http://www.spoj.com/problems/SBANK/
46. https://goo.gl/FxvqiP
47. https://goo.gl/s1gkhH
48. http://www.spoj.com/problems/RMQSQ/ [sparse table]
49. http://codeforces.com/problemset/problem/596/D
50. https://goo.gl/oXTucZ
51. http://www.spoj.com/problems/INVCNT/
52. http://www.spoj.com/problems/GSS3/
53. http://codeforces.com/problemset/problem/340/D
54. http://www.spoj.com/problems/RMID2/ [heaps]
55. http://www.spoj.com/problems/DCEPC206/
56. http://www.spoj.com/problems/BRIDGE/
57. http://www.spoj.com/problems/KGSS/
58. https://www.hackerrank.com/challenges/counter-game/problem
59. https://www.hackerrank.com/challenges/and-product/problem
60. https://goo.gl/gngBzX
61. http://www.spoj.com/problems/BISHOPS/
62. http://www.spoj.com/problems/ADAFRIEN/
63. http://www.spoj.com/problems/POTHOLE/
64. https://www.hackerrank.com/challenges/task-scheduling/problem
65. http://www.spoj.com/problems/MKTHNUM/
66. http://codeforces.com/contest/510/problem/C
67. https://www.hackerrank.com/challenges/the-great-xor/problem
68. http://www.spoj.com/problems/BACKUP/ [heaps]
69. https://goo.gl/5ztFts
70. https://www.hackerrank.com/challenges/bike-racers/problem
71. https://www.hackerrank.com/challenges/yet-another-minimax-problem/problem
72. http://codeforces.com/problemset/problem/761/D

Hard

1. https://www.hackerrank.com/challenges/hamming-distance/problem
2. http://www.spoj.com/problems/BRDGHRD/
3. http://www.spoj.com/problems/AGGRCOW/
4. http://www.spoj.com/problems/SUBXOR/ [trie]
5. http://codeforces.com/contest/538/problem/F
6. https://www.hackerrank.com/challenges/board-cutting/problem
7. http://codeforces.com/problemset/problem/653/F [persistent segTree]
8. https://www.hackerrank.com/challenges/string-transmission/problem
9. http://codeforces.com/contest/506/problem/D [sparse table]
10. http://codeforces.com/problemset/problem/903/E
11. https://www.codechef.com/problems/MONOPLOY [HLD]
12. http://www.spoj.com/problems/GSS7/ [HLD]
13. http://www.spoj.com/problems/KATHTHI/
14. http://codeforces.com/problemset/problem/780/F
15. https://www.hackerrank.com/challenges/save-humanity/problem
16. https://goo.gl/MvotAY
17. http://codeforces.com/problemset/problem/813/E [persistent segTree]
18. http://www.spoj.com/problems/ASSIGN/
19. https://www.codechef.com/problems/CL16BF
20. http://www.spoj.com/problems/SKYLINE2/
21. http://www.spoj.com/problems/RPLA/
22. https://goo.gl/HgGzcJ
23. http://www.spoj.com/problems/LONGCS/ [suffix tree or suffix array]
24. https://www.hackerrank.com/challenges/stonegame/problem
25. http://codeforces.com/problemset/problem/678/E
26. http://www.spoj.com/problems/SSORT/
27. http://www.spoj.com/problems/INUMBER/
28. https://goo.gl/SVvLEA
29. https://www.hackerrank.com/challenges/2s-complement/problem
30. https://goo.gl/nqXngJ
31. https://www.hackerrank.com/challenges/iterate-it/problem
32. https://www.codechef.com/problems/DGCD
33. http://www.spoj.com/problems/ANARC05H/