Problem

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

Explanation:

The strings s and t can be made identical by:

  • Mapping 'e' to 'a'.
  • Mapping 'g' to 'd'.

Example 2:

Input: s = “foo”, t = “bar”

Output: false

Explanation:

The strings s and t can not be made identical as 'o' needs to be mapped to both 'a' and 'r'.

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.

Solve

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class Solution:
    def isIsomorphic(self, s: str, t: str) -> bool:
        if len(s) != len(t):
            return False
        
        st_map = {}
        ts_map = {}
        
        for i in range(len(s)):
            if s[i] not in st_map:
                st_map[s[i]] = t[i]
            if t[i] not in ts_map:
                ts_map[t[i]] = s[i]
            
            if st_map[s[i]] != t[i] or ts_map[t[i]] != s[i]:
                return False
        
        return True

還不錯的

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class Solution:
    def isIsomorphic(self, s: str, t: str) -> bool:
        s_map = []
        t_map = []

        for c in s:
            s_map.append(s.index(c))
        
        for c in t:
            t_map.append(t.index(c))
        if s_map == t_map:
            return True
        return False