205_Isomorphic_Strings.py

# Given two strings s and t, determine if they are isomorphic.

# Two strings s and t are isomorphic if the characters in s can be replaced to get t.

# All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character, but a character may map to itself.

 

# Example 1:

# Input: s = "egg", t = "add"
# Output: true
# Example 2:

# Input: s = "foo", t = "bar"
# Output: false
# Example 3:

# Input: s = "paper", t = "title"
# Output: true
 

# Constraints:

# 1 <= s.length <= 5 * 104
# t.length == s.length
# s and t consist of any valid ascii character.

class Solution:
    def isIsomorphic(self, s: str, t: str) -> bool:
        if len(s) == len(t):
            dict_letters = {}
            for i in range(len(s)):
                if dict_letters.get(s[i]) == None:
                    if t[i] in dict_letters.values():
                        return False
                    dict_letters[s[i]] = t[i]
                elif dict_letters[s[i]] != t[i]:
                    return False
            return True
        else:
            return False