solution.kt

/**
 * Sales by Match
 * 
 * @author Dela Anthonio
 * @hackerrank https://hackerrank.com/delaanthonio
 * @problem https://www.hackerrank.com/challenges/sock-merchant
 */

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 sockMerchant function below.
fun sockMerchant(n: Int, array: Array<Int>): Int {
    var map = hashMap()
    for (x in array) {
        val count = map.getOrElse(x, 0)
        map.put(x, count + 1)
    }
    val counts = map.values.map(x -> x / 2)
    counts.foldRight(x,y -> x + y)
}

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

    val n = scan.nextLine().trim().toInt()

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

    val result = sockMerchant(n, array)

    println(result)
}