add 1128 prod variant

Author: Ashwagandha-coder

contest/src/main/java/com/github/contest/Execute.kt

@@ -2,6 +2,8 @@ package com.github.contest
 
 
 import com.github.contest.hashTable.countGoodAlternativeSolution
+import com.github.contest.hashTable.numEquivDominoPairsProdVariant
+import com.github.contest.hashTable.testing
 import com.github.contest.math.numberOfPowerfulInt
 import com.github.contest.strings.fullJustify
 import com.github.contest.strings.subStrHash
@@ -14,7 +16,11 @@ import java.util.TreeMap
 
 fun main() {
 
-
+    numEquivDominoPairsProdVariant(
+        arrayOf(
+            intArrayOf(1, 2), intArrayOf(2, 1), intArrayOf(3, 4), intArrayOf(5, 6)
+        )
+    ).also { println(it) }
 }
 
 fun countGoodData() {

contest/src/main/java/com/github/contest/hashTable/HashTableProdVariant.kt

@@ -110,3 +110,16 @@ fun intToRomanProdVariant(num: Int): String {
     }
 }
 
+/**
+ * 1128. Number of Equivalent Domino Pairs
+ */
+
+fun numEquivDominoPairsProdVariant(dominoes: Array<IntArray>): Int = dominoes
+    .map { (a, b) -> if (a <= b) a to b else b to a }
+    .groupingBy { it }
+    .eachCount()
+    .values
+    .sumOf { count -> count * (count - 1) / 2 }
+
+
+