https://www.hackerrank.com/challenges/staircase/problem

Staircase - OOP.kt

import java.util.Scanner

fun main(args: Array<String>) {
    val inputReader = Scanner(System.`in`)
    val input = inputReader.nextLine()
    
    val sizeOfStairs = input.toInt()
    
    StaircaseBuilder()
        .build(sizeOfStairs)
        .print()
}

class StaircaseBuilder() {
    
    fun build(size: Int): Staircase {
        var stairs = Array<Step>(size) { i ->
            Step(width=i+1)
        }
        return Staircase(stairs)
    }
}

class Staircase(var stairs: Array<Step>) {
    
    fun print() {
        for (step in stairs)
            System.out.println(step.renderMirrored(stairs.size))
    }
}

class Step(val width: Int) {
    val HASH = '#'
    val SPACE = ' '
    
    fun renderMirrored(staircaseWidth: Int): String {
        var output = ""
        for (i in 1..staircaseWidth) {
            if (i <= staircaseWidth - width)
                output += SPACE
            else
                output += HASH
        }
        return output
    }
}