HackerRank/Algorithm/BalancedBrackets kotlin

BalancedBrackets.kt

import java.util.*

const val RESULT_YES = "YES"
const val RESULT_NO = "NO"

fun isBalanced(s: String): String {
    val stack = Stack<Char>()
    s.forEach { char ->
        when (char) {
            '[' -> stack.push(']')
            '{' -> stack.push('}')
            '(' -> stack.push(')')
            else -> {
                if (stack.isEmpty() || stack.pop() != char) {
                    return RESULT_NO
                }
            }
        }
    }
    return if (stack.isEmpty()) {
        RESULT_YES
    } else {
        RESULT_NO
    }
}

fun main(args: Array<String>) {
    repeat(readln().toInt()) {
        println(isBalanced(readln()))
    }
}