205. Isomorphic Strings.md

205. Isomorphic Strings

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.

Python:

class Solution:
    def isIsomorphic(self, s: str, t: str) -> bool:
        if len(s) != len(t): return False
        d = {}
        for i in range(len(s)):
            if s[i] not in d: d[s[i]] = t[i]
            else:
                if d[s[i]] != t[i]: return False
        return len(set(d.values())) == len(d.values())