diff --git a/Problem1.java b/Problem1.java
index e69de29b..052ef342 100644
--- a/Problem1.java
+++ b/Problem1.java
@@ -0,0 +1,16 @@
+class Solution {
+    public int[] twoSum(int[] nums, int target) {
+        HashMap<Integer, Integer> diffIndex = new HashMap<>();
+        for(int i =0; i< nums.length; i++) {
+            int diff = target - nums[i];
+            if(diffIndex.containsKey(diff)) {
+             int res = diffIndex.get(diff);
+             return new int[]{i, res};
+            } else {
+                diffIndex.put(nums[i], i);
+            }
+
+        }
+        return new int[]{-1, -1};
+    }
+}
\ No newline at end of file