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: All inputs will be in lower-case.

class Solution {public:    vector<vector<string>> groupAnagrams(vector<string>& strs) {        vector<vector<string>> res;        unordered_map<string,vector<int>> data;        //unordered_map<string, vector<int>>::iterator got;        for(int i = 0; i < strs.size(); i++)        {            string tmp = strs[i];            sort(tmp.begin(), tmp.end());            data[tmp].push_back(i);        }        for(unordered_map<string, vector<int>>::iterator it=data.begin(); it!=data.end(); it++)        {            vector<string> group;            for(int i = 0; i <it->second.size(); i++)            {                group.push_back(strs[it->second[i]]);            }            res.push_back(group);        }        return res;    }};