https://leetcode.cn/problems/group-anagrams/?envType=study-plan-v2&envId=top-100-liked
ĸλʷ 

class Solution {
public:
    vector<vector<string>> groupAnagrams(vector<string>& strs) {
        vector<vector<string>> result;
        unordered_map<string,vector<string>> hash;
        for(auto& e : strs)
        {
            string t = e;
            sort(t.begin(), t.end());
            hash[t].push_back(e);
        }

        for(auto& e : hash)
        {
            result.push_back(e.second);
        }

        return result;
    }
};
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