Given an array of strings, return all groups of strings that are anagrams. Note: All inputs will be in lower-case. http://leetcode.com/onlinejudge#question_49

leetcode_anagrams.cpp

class Solution {
public:
    vector<string> anagrams(vector<string> &strs) {
        vector<string> ans;
        map<string, int> M;
        for (int i = 0; i < strs.size(); ++i) {
            string tmp = strs[i];
            sort(tmp.begin(), tmp.end());
            try {
                M[tmp]++;
            }
            catch (exception& e) {
                M[tmp] = 1;
            }
        }
        for (int i = 0; i < strs.size(); ++i) {
            string tmp = strs[i];
            sort(tmp.begin(), tmp.end());
            if (M[tmp] >= 2)
                ans.push_back(strs[i]);
        }
        return ans;
    }
};