two sum

Author: iam-edwin

two-sum/iam-edwin.kt

@@ -0,0 +1,22 @@
+class Solution {
+    fun twoSum(nums: IntArray, target: Int): IntArray {
+        val indexMap = nums.mapIndexed { index, num -> num to index }
+            .groupBy({ it.first }, {it.second})
+
+        indexMap.forEach { (firstNum, firstIndicies) ->
+            val secondNum = target - firstNum
+            if (firstNum == secondNum) {
+                if (firstIndicies.size > 1) {
+                    return intArrayOf(firstIndicies[0], firstIndicies[1])
+                }
+            } else {
+                val secondIndicies = indexMap[secondNum]
+                if (secondIndicies != null) {
+                    return intArrayOf(firstIndicies[0], secondIndicies[0])
+                }
+            }
+        }
+        
+        return intArrayOf()
+    }
+}