HackerRank/Algorithm/LonelyInteger kotlin

LonelyInteger.kt

import kotlin.*

fun lonelyinteger(a: Array<Int>): Int =
    a.groupingBy { it }
        .eachCount()
        .filterValues { it == 1 }
        .entries
        .single()
        .key

fun main(args: Array<String>) {
    val n = readln().trim().toInt()

    val a = readln().trimEnd()
        .split(" ")
        .map(String::toInt)
        .toTypedArray()

    val result = lonelyinteger(a)

    println(result)
}