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 transformString(self, s: str) -> str:
        index_mapping = {}
        new_str = []
        
        for i, c in enumerate(s):
            if c not in index_mapping:
                index_mapping[c] = i
            new_str.append(str(index_mapping[c]))
        
        return " ".join(new_str)
    
    def isIsomorphic(self, s: str, t: str) -> bool:
        return self.transformString(s) == self.transformString(t)