049.md

Group Anagrams

题目

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.

思路

 ["ate", "eat","tea"] 排序的结果为 aet
 ["nat","tan"] 排序的结果为 atn
 ["bat"] 排序结果为 abt
 
 放在一起的单词，排序相同，可以设置hash(string,vector<string>) 前面为排序后的单词，后面为相同的排序结果的单词。
 取出每一个单词str:   hash[alpha].push_back[str]即可。

代码

class Solution {
public:
    vector<vector<string>> groupAnagrams(vector<string>& strs) {
        unordered_map<string,vector<string>> mp;//unordered_map内部不排序
        vector<vector<string>> result;
        int sz = strs.size();
        for(int i=0;i<sz;++i){
            string temp = strs[i];
            sort(temp.begin(),temp.end()); 
            mp[temp].push_back(strs[i]);//排序相同的放在同一个vector里面
        }
       
        for(auto iter_beg=mp.begin();iter_beg!=mp.end();++iter_beg){
            result.push_back(iter_beg->second);
        }
        return result;
    }
};