kt: add «1726. Tuple with Same Product»

URL:	https://leetcode.com/problems/tuple-with-same-product/
Signed-off-by: Matej Focko <me@mfocko.xyz>

kt/tuple-with-same-product.kt

@@ -0,0 +1,16 @@
+class Solution {
+    fun tupleSameProduct(nums: IntArray): Int =
+        buildMap<Int, Int> {
+            nums.indices
+                .flatMap { i ->
+                    nums.indices.drop(i + 1).map { j ->
+                        nums[i] to nums[j]
+                    }
+                }.forEach { (x, y) ->
+                    put(x * y, 1 + (get(x * y) ?: 0))
+                }
+        }.entries.sumOf { (p, count) ->
+            val pairs = (count - 1) * count / 2
+            8 * pairs
+        }
+}