12. Group Anagrams.cpp

/*
Group Anagrams
==============

Given an array of strings strs, group the anagrams together. You can return the answer in any order.

An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.

Example 1:
Input: strs = ["eat","tea","tan","ate","nat","bat"]
Output: [["bat"],["nat","tan"],["ate","eat","tea"]]

Example 2:
Input: strs = [""]
Output: [[""]]

Example 3:
Input: strs = ["a"]
Output: [["a"]]

Constraints:
1 <= strs.length <= 104
0 <= strs[i].length <= 100
strs[i] consists of lower-case English letters.
*/

class Solution
{
public:
    vector<vector<string>> groupAnagrams(vector<string> &S)
    {
        unordered_map<string, vector<string>> strs;

        for (auto &i : S)
        {
            auto sorted = i;
            sort(sorted.begin(), sorted.end());
            strs[sorted].push_back(i);
        }

        vector<vector<string>> ans;
        for (auto &i : strs)
            ans.push_back(i.second);

        return ans;
    }
};