49. Group Anagrams | LeetCode Solution

49. Group Anagrams | LeetCode Solution

 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 lowercase English letters.

The solution to the above question is-

class Solution

{

public:

  vector<vector<string>> groupAnagrams(vector<string> &strs)

  {

    unordered_map<string, vector<string>> mymap;

    for (string s : strs)

    {

      string curr = s;

      sort(s.begin(), s.end());

      auto it = mymap.find(s);

      if (it == mymap.end())

      {

        mymap[s] = {curr};

      }

      else

      {

        it->second.push_back(curr);

      }

    }

    vector<vector<string>> ans;

    for (auto it = mymap.begin(); it != mymap.end(); it++)

    {

      ans.push_back(it->second);

    }

    return ans;

  }

};