205. Isomorphic Strings.cpp

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

Two strings 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
Note:
You may assume both s and t have the same length.
*/

class Solution {
public:
    bool isIsomorphic(string s, string t) {
        if ( s.size() != t.size() ) return false;
        vector<int> m1( 256, 0 );
        vector<int> m2( 256, 0 );
        for ( int i = 0; i < s.size(); ++i )
        {
            if ( m1[s[i]] != m2[t[i]] ) return false;
            m1[s[i]] = i + 1;
            m2[t[i]] = i + 1;
        }
        return true;
    }
};