leetcode——205——Isomorphic Strings

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.

For example,
Given "egg", "add", return true.

Given "foo", "bar", return false.

Given "paper", "title", return 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;
           
        unordered_map<char,char> m1;
        unordered_map<char,char> m2;
        for(int i = 0; i<s.size();i++)
        {
            if(m1.find(s[i])!=m1.end()&&m1[s[i]]!=t[i])
                return false;
            m1[s[i]]=t[i];
            
            
             if(m2.find(t[i])!=m2.end()&&m2[t[i]]!=s[i])
                return false;
            
            m2[t[i]]=s[i];
        }
        
        return true;
    }
};