LeetCode-in-Cpp

49. Group Anagrams

Medium

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.

Solution

#include <vector>
#include <string>
#include <unordered_map>
#include <algorithm>

class Solution {
public:
    std::vector<std::vector<std::string>> groupAnagrams(std::vector<std::string>& strs) {
        std::unordered_map<std::string, std::vector<std::string>> hm;
        for (const auto& s : strs) {
            std::string temp = s;
            std::sort(temp.begin(), temp.end());
            hm[temp].push_back(s);
        }
        std::vector<std::vector<std::string>> result;
        for (auto& pair : hm) {
            result.push_back(std::move(pair.second));
        }
        return result;
    }
};

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