LeetCode 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.

题目：看看两个单词是否同构。这是一个明显的hash表的问题，但是要注意没有两个字母对应着一个字母，但是同一个字母可以对着自己本身

class Solution {
public:
    bool isIsomorphic(string s, string t) {
        map<char, char> chChMap,chChMap2;
        for (unsigned i = 0;i < s.size();++i)
        {
            
            if (chChMap.find(s[i]) == chChMap.end())
                chChMap[s[i]] = t[i];
            else if (t[i] != chChMap[s[i]])
                return false;
            if (chChMap2.find(t[i]) == chChMap2.end())
                chChMap2[t[i]] = s[i];
            else if (s[i] != chChMap2[t[i]])
                return false;
        }
        return true;
    }
};