Group Anagrams

🔗 문제 링크

https://leetcode.com/problems/group-anagrams/

🔍 문제 설명

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.

⚠️ 제한사항

• $1 <= strs.length <= 10^4$

• $0 <= strs[i].length <= 100$

• $strs[i]$ consists of lowercase English letters.

🗝 풀이 (언어 : Java)

anagram은 단어들을 알파벳순으로 정렬했을 때 결과가 같으면 anagram이다. 반복문을 한번만 돌고 해결하기 위해서 HashMap을 이용했다.

import java.util.*;

class Solution {
    public List<List<String>> groupAnagrams(String[] strs) {
        List<List<String>> answer = new ArrayList<>();
        Map<String, List<String>> map = new HashMap<>();
        for (String s : strs) {
            char[] arr = s.toCharArray();
            Arrays.sort(arr);
            String sorted = String.valueOf(arr);
            if (map.containsKey(sorted))
                map.get(sorted).add(s);
            else
                map.put(sorted, new ArrayList<>(Arrays.asList(s)));
        }
        answer.addAll(map.values());
        return answer;
    }
}