g0001_0100.s0012_integer_to_roman.Solution.kt Maven / Gradle / Ivy

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Kotlin-based LeetCode algorithm problem solutions, regularly updated

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package g0001_0100.s0012_integer_to_roman

// #Medium #String #Hash_Table #Math #2023_07_03_Time_180_ms_(98.25%)_Space_37_MB_(82.89%)

class Solution {
    fun intToRoman(num: Int): String {
        var localNum = num
        val sb = StringBuilder()
        val m = 1000
        val c = 100
        val x = 10
        val i = 1
        localNum = numerals(sb, localNum, m, ' ', ' ', 'M')
        localNum = numerals(sb, localNum, c, 'M', 'D', 'C')
        localNum = numerals(sb, localNum, x, 'C', 'L', 'X')
        numerals(sb, localNum, i, 'X', 'V', 'I')
        return sb.toString()
    }

    private fun numerals(sb: StringBuilder, num: Int, one: Int, cTen: Char, cFive: Char, cOne: Char): Int {
        val div = num / one
        when (div) {
            9 -> {
                sb.append(cOne)
                sb.append(cTen)
            }
            8 -> {
                sb.append(cFive)
                sb.append(cOne)
                sb.append(cOne)
                sb.append(cOne)
            }
            7 -> {
                sb.append(cFive)
                sb.append(cOne)
                sb.append(cOne)
            }
            6 -> {
                sb.append(cFive)
                sb.append(cOne)
            }
            5 -> sb.append(cFive)
            4 -> {
                sb.append(cOne)
                sb.append(cFive)
            }
            3 -> {
                sb.append(cOne)
                sb.append(cOne)
                sb.append(cOne)
            }
            2 -> {
                sb.append(cOne)
                sb.append(cOne)
            }
            1 -> sb.append(cOne)
        }
        return num - div * one
    }
}