diff --git a/src/leetcode/string.md b/src/leetcode/string.md
index f3ad14f..aeb2132 100644
--- a/src/leetcode/string.md
+++ b/src/leetcode/string.md
@@ -1 +1,22 @@
-# String
\ No newline at end of file
+# String
++ [Group Anagrams](#group-anagrams)
+## Group Anagrams
+https://leetcode.com/problems/group-anagrams/
+```java
+class Solution {
+    public List<List<String>> groupAnagrams(String[] strs) {
+        HashMap<String, ArrayList<String>> map = new HashMap<>();
+        for (String s: strs) {
+            char[] ch = s.toCharArray();
+            Arrays.sort(ch);
+            String key = String.valueOf(ch);
+            if (!map.containsKey(key)) {
+                map.put(key, new ArrayList<>());
+            }
+            map.get(key).add(s);
+        }
+        return new ArrayList<>(map.values());
+    }
+}
+
+```