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205. Isomorphic Strings

Difficulty Topics

Description

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.

Solution

isomorphic-strings.py
class Solution:
    def isIsomorphic(self, s: str, t: str) -> bool:

        def construct(s):
            s = list(s)
            mp = {}
            res = ""

            for i, x in enumerate(s):
                if x not in mp:
                    mp[x] = len(mp)
                s[i] = mp[x]

            return s

        return construct(s) == construct(t)