Group Anagrams

Given an array of strings, group anagrams together.

For example, given: ["eat", "tea", "tan", "ate", "nat", "bat"],

Return:

[ ["ate", "eat","tea"], ["nat","tan"], ["bat"] ]

Solution:

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