Create 15.3Sum.kt

Author: VinayByte

15.3Sum.kt

@@ -0,0 +1,48 @@
+/**
+ * Created by VINAY on 11-08-2024.
+ * Github:@vinayByte
+ *
+ */
+//O(n^2)
+fun threeSum(nums: IntArray): List<List<Int>> {
+    val result = mutableSetOf<List<Int>>()
+    val n = nums.size
+    val sortedNums = nums.sorted()
+    for (i in 0 until n) {
+        var left = i + 1
+        var right = n - 1
+        while (left < right) {
+            var sum = sortedNums[i] + sortedNums[left] + sortedNums[right]
+            if (sum == 0) {
+                val triplet = listOf(sortedNums[i], sortedNums[left], sortedNums[right])
+                result.add(triplet)
+                left++
+                right--
+            } else if (sum < 0) {
+                left++
+            } else {
+                right--
+            }
+        }
+    }
+
+    return result.toList()
+}
+
+//Brute Force: O(n3)
+fun threeSum1(nums: IntArray): List<List<Int>> {
+    val result = mutableSetOf<List<Int>>()
+    val n = nums.size
+
+    for (i in 0 until n) {
+        for (j in i + 1 until n) {
+            for (k in j + 1 until n) {
+                if ((nums[i] + nums[j] + nums[k] == 0) && (i != j && i != k && j != k)) {
+                    val triplet = listOf(nums[i], nums[j], nums[k]).sorted()
+                    result.add(triplet)
+                }
+            }
+        }
+    }
+    return result.toList()
+}