Added Solution for LeetCode Problem No. 49

Author: ps729

LeetCode/49. Group Anagrams/Solution.java

@@ -0,0 +1,29 @@
+// https://leetcode.com/problems/group-anagrams/
+
+class Solution {
+    public List<List<String>> groupAnagrams(String[] s) {
+        if (s.length == 1) {
+            List<String> list = new ArrayList<>(1);
+            list.add(s[0]);
+            List<List<String>> res = new ArrayList<>(1);
+            res.add(list);
+            return res;
+        }
+        Map<String, List<String>> map = new HashMap<>();
+        for (String word : s) {
+            char[] alphabet = new char[26];
+            for (char c : word.toCharArray()) {
+                alphabet[c - 'a']++;
+            }
+            String key = new String(alphabet);
+            if (map.containsKey(key)) {
+                map.get(key).add(word);
+            } else {
+                List<String> list = new ArrayList<>();
+                list.add(word);
+                map.put(key,list);
+            }
+        }
+        return new ArrayList<>(map.values());
+    }
+}