diff --git a/src/main/kotlin/math/TwoSum.kt b/src/main/kotlin/math/TwoSum.kt
index 9ca0657..77e324a 100644
--- a/src/main/kotlin/math/TwoSum.kt
+++ b/src/main/kotlin/math/TwoSum.kt
@@ -24,3 +24,37 @@ fun twoSum(nums: IntArray, target: Int): IntArray{
     return intArrayOf(0,1)
 
 }
+
+/**
+ * Approach 2: Using HashMap
+ *
+ * Complexity Analysis:
+ *
+ * Time complexity: O(n)
+ * Space complexity: O(n)
+ *
+ * Create an empty mutableMap and for every num in nums
+ * if map contains target-num, return num and target-num,
+ * otherwise add num, this approach returns all distinct pairs
+ * of such pairs.
+ * @param nums Array of integers.
+ * @param target Integer target.
+ * @return the two numbers such that they add up to target.
+ */
+fun twoSumOptimised(nums: IntArray, target: Int): Array<Pair<Int, Int>>{
+
+    val array: MutableList<Pair<Int, Int>> = mutableListOf()
+    val map: MutableMap<Int, Int> = HashMap()
+    for(num  in nums) {
+        val targetDiff = target - num;
+        if(map[targetDiff] == null)
+            map[num] = 1
+        else {
+            array.add(Pair(targetDiff, num))
+        }
+    }
+
+    return array.toTypedArray()
+
+
+}
diff --git a/src/test/kotlin/math/TwoSum.kt b/src/test/kotlin/math/TwoSum.kt
index 7e5e00f..e38d247 100644
--- a/src/test/kotlin/math/TwoSum.kt
+++ b/src/test/kotlin/math/TwoSum.kt
@@ -12,4 +12,14 @@ class TwoSumTest {
         val result = intArrayOf(0,1)
         assert(twoSum(array,target).contentEquals(result))
     }
+
+    @Test
+    fun testTwoSumOptimised(){
+        val array = intArrayOf(1, 0, -1, 2, 4, 5, 3, 2)
+        val target: Int = 4
+        val result = twoSumOptimised(array, target).apply {
+            this.all { it.first + it.second == target }
+        }
+        assert(result.isNotEmpty())
+    }
 }
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