49. Group Anagrams

Given an array of strings, group anagrams together.

For example, given: ["eat", "tea", "tan", "ate", "nat", "bat"], 
Return:

[  ["ate", "eat","tea"],  ["nat","tan"],  ["bat"]]

Note:

1. For the return value, each inner list's elements must follow the lexicographic order.

1. All inputs will be in lower-case.

这里主要是map和set的运用。

代码：

class Solution {public:vector<vector<string> > groupAnagrams(vector<string>& strs){int n=strs.size();vector<vector<string> >res;unordered_map<string,multiset<string> >m;for(int i=0;i<n;i++){string tmp=strs[i];sort(tmp.begin(),tmp.end());m[tmp].insert(strs[i]);} unordered_map<string,multiset<string> >::iterator it;for(it=m.begin();it!=m.end();it++){vector<string>vec((*it).second.begin(),(*it).second.end());res.push_back(vec);}return res;}};