Group Anagrams

 Group Anagrams

Given an array of strings strs, group the anagrams together. You can return the answer in any order.

Example 1:

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

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

Explanation:

• There is no string in strs that can be rearranged to form "bat".
• The strings "nat" and "tan" are anagrams as they can be rearranged to form each other.
• The strings "ate", "eat", and "tea" are anagrams as they can be rearranged to form each other.

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

class Solution {

public List<List<String>> groupAnagrams(String[] strs) {

Map<String, List<String>> map = new HashMap<>();

for(String word : strs) {

char[] chars = word.toCharArray();

Arrays.sort(chars);

String sortedWord = new String(chars);

if(!map.containsKey(sortedWord)) {

map.put(sortedWord, new ArrayList<String>());

}

map.get(sortedWord).add(word);

}

return new ArrayList<>(map.values());

}

}