字符串 leetcode 387. First Unique Character in a String

原题链接：First Unique Character in a String

题解：

class Solution {
public:
    int firstUniqChar(string s) {
        map<char,int>mm;
        for(int i=0;i<s.size();i++)mm[s[i]]++;
        for(int i=0;i<s.size();i++)if(mm[s[i]]==1)return i;  
        return -1;
    }
};