0049 - Group Anagrams

0049 - 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.

Examples

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

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

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

Constraints

• 1 <= strs.length <= 104

• 0 <= strs[i].length <= 100

• strs[i] consists of lowercase English letters.

Java Solution

class Solution {
    public List<List<String>> groupAnagrams(String[] strs) {
        Map<String, List> result = new HashMap<String, List>();
        
        for(String str : strs) {
            char[] chars = str.toCharArray();
            Arrays.sort(chars);
            String key = String.valueOf(chars);
            if(!result.containsKey(key)) result.put(key, new ArrayList());
            result.get(key).add(str);
        }
        return new ArrayList(result.values());
    }
}