anagrams

题目：

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

程序：

class Solution {public:    vector<string> anagrams(vector<string> &strs) {        vector<string> result;        int l = strs.size();        if(l == 0)            return result;        map<string,int> mapping;        for(int i=0;i<l;i++)        {            string tmp = strs[i];            sort(tmp.begin(),tmp.end());            if(mapping.find(tmp) == mapping.end())                mapping[tmp] = i;            else{                if(mapping[tmp] >= 0)                {                    result.push_back(strs[mapping[tmp]]);                    mapping[tmp] = -1;                }                result.push_back(strs[i]);            }        }        return result;    }};

点评：

哈希表，降低时间复杂度