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<>());
}
map.get(s).add(strs[i]);
}
for (String key : map.keySet()) {
ans.add(map.get(key));
}
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;
}
}