Group anagram java

solutions/Group_Anagram.java

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+import java.util.*;
+
+public class Group_Anagram {
+    public List<List<String>> groupAnagrams(String[] strs) {
+        Map<String, List<String>> res = new HashMap<>;
+
+        for(String s : strs){
+            int[] count = new int[26];
+            for(char c : s.toCharArray()){
+                count[c - 'a']++;
+            }
+
+            String key = Arrays.toString(count);
+            res.putIfAbsent(key, new ArrayList<>);
+            res.get(key).add(s);
+        }
+        return new ArrayList<>(res.values());
+    }
+}

solutions/Two_Sum.java

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+import java.util.HashMap;
+
+public class Two_Sum {
+        public int[] twoSum(int[] nums, int target) {
+            HashMap<Integer, Integer> prevMap = new HashMap<>();
+
+            for (int i = 0; i < nums.length; i++) {
+                int num = nums[i];
+                int diff = target - num;
+
+
+                if (prevMap.containsKey(diff)) {
+                    return new int[]{prevMap.get(diff), i};
+                }
+                prevMap.put(num, i);
+            }
+            return new int[]{};
+        }
+    }
+