DivisibleSumPairs.kt

/* You are given an array of n integers, ar = [ar[0], ar[1],...,ar[n-1]], and a positive integer, k. 
 * Find and print the number of (i, j) pairs where i<j and ar[i] + ar[j] is divisible by k.
 */


import java.io.*
import java.math.*
import java.security.*
import java.text.*
import java.util.*
import java.util.concurrent.*
import java.util.function.*
import java.util.regex.*
import java.util.stream.*
import kotlin.collections.*
import kotlin.comparisons.*
import kotlin.io.*
import kotlin.jvm.*
import kotlin.jvm.functions.*
import kotlin.jvm.internal.*
import kotlin.ranges.*
import kotlin.sequences.*
import kotlin.text.*

// Complete the divisibleSumPairs function below.
fun divisibleSumPairs(n: Int, k: Int, ar: Array<Int>): Int {

    var count: Int = 0
    for (i in 0..n-2) {
        for (j in i+1..n-1) {
            val total = ar[i] + ar[j]
            if (total % k == 0)
                count++
        }
    }
    return count
}

fun main(args: Array<String>) {
    val scan = Scanner(System.`in`)

    val nk = scan.nextLine().split(" ")

    val n = nk[0].trim().toInt()

    val k = nk[1].trim().toInt()

    val ar = scan.nextLine().split(" ").map{ it.trim().toInt() }.toTypedArray()

    val result = divisibleSumPairs(n, k, ar)

    println(result)
}