Anagrams [LeetCode]

Given an array of strings, return all groups of strings that are anagrams.

Note: All inputs will be in lower-case.

Summary: To sort and compare strings, using map to record distinct strings.

 1 class Solution {
 2 public:
 3     vector<string> anagrams(vector<string> &strs) {
 4         vector<string> result;
 5         map<string, int> str_map;
 6         for(int i = 0; i < strs.size(); i ++) {
 7             string tmp = strs[i];
 8             std::sort(tmp.begin(), tmp.end());
 9             if(str_map.find(tmp) == str_map.end()) {
10                 str_map[tmp] = i;
11             }else {
12                 result.push_back(strs[i]);
13                 if(str_map[tmp] >= 0 ) {
14                     result.push_back(strs[str_map[tmp]]);
15                     str_map[tmp] = -1;
16                 }
17             }
18         }
19         return result;
20     }
21 };