#171 Anagrams

题目描述：

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

 Notice

All inputs will be in lower-case

Have you met this question in a real interview? 

Yes

Example

Given ["lint", "intl", "inlt", "code"], return["lint", "inlt", "intl"].

Given ["ab", "ba", "cd", "dc", "e"], return["ab", "ba", "cd", "dc"].

Challenge 

What is Anagram?
- Two strings are anagram if they can be the same after change the order of characters.

题目思路：

这题我就用了一个hash map，它的key是排序好了的string，value是一个string vector，里面存的是给的array里面sorted（string）== key的string们。

Mycode（AC = 69ms）：

class Solution {public:        /**     * @param strs: A list of strings     * @return: A list of strings     */    vector<string> anagrams(vector<string> &strs) {        // write your code here        vector<string> ans;        map<string, vector<string>> helper;                // sort each string and put it into the map        for (int i = 0; i < strs.size(); i++) {            string sorted = strs[i];            sort(sorted.begin(), sorted.end());                        helper[sorted].push_back(strs[i]);        }                for (auto it = helper.begin(); it != helper.end(); it++) {            if (it->second.size() > 1) {                push_ans(ans, it->second);            }        }                return ans;    }        void push_ans(vector<string>& ans, vector<string>& strs) {        for (int i = 0; i < strs.size(); i++) {            ans.push_back(strs[i]);        }    }};