# 49. Group Anagrams (Medium)

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

Given an array of strings, group anagrams together.

Example:

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

Note:

• All inputs will be in lowercase.
• The order of your output does not matter.

## Solutions

class Solution {

public List<List<String>> groupAnagrams(String[] strs) {
List<List<String>> ans = new ArrayList<>();
if (strs == null || strs.length == 0) {
return ans;
}

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

for (int i = 0; i < strs.length; i++) {
String s = sort(strs[i]);
if (!map.containsKey(s)) {
map.put(s, new ArrayList<>());
}

}

for (String key : map.keySet()) {
}

return ans;
}

private String sort(String s) {
if (s == null) {
return null;
}

if (s.length() == 1) {
return s;
}

char[] chars = s.toCharArray();
Arrays.sort(chars);

String ans = "";
for (int i = 0; i < chars.length; i++) {
ans += chars[i];
}

return ans;
}
}