leetcode---anagrams---字符串

Given an array of strings, return all groups of strings that are anagrams.
Note: All inputs will be in lower-case.

class Solution {public:    vector<string> anagrams(vector<string> &strs)     {        vector<string> ans;        int n = strs.size();        if(n == 0)            return ans;        map<string, int> m;        vector<bool> ok(n, false);        for(int i=0; i<n; i++)        {            string str = strs[i];            sort(str.begin(), str.end());            m[str]++;        }        for(int i=0; i<n; i++)        {            string str = strs[i];            sort(str.begin(), str.end());            if(m[str] > 1)                ans.push_back(strs[i]);        }        return ans;    } };