96 lines
2.3 KiB
Kotlin
96 lines
2.3 KiB
Kotlin
// version 1.1
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data class Fangs(val fang1: Long = 0L, val fang2: Long = 0L)
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fun pow10(n: Int): Long = when {
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n < 0 -> throw IllegalArgumentException("Can't be negative")
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else -> {
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var pow = 1L
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for (i in 1..n) pow *= 10L
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pow
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}
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}
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fun countDigits(n: Long): Int = when {
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n < 0L -> throw IllegalArgumentException("Can't be negative")
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n == 0L -> 1
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else -> {
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var count = 0
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var nn = n
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while (nn > 0L) {
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count++
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nn /= 10L
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}
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count
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}
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}
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fun hasTrailingZero(n: Long): Boolean = when {
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n < 0L -> throw IllegalArgumentException("Can't be negative")
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else -> n % 10L == 0L
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}
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fun sortedString(s: String): String {
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val ca = s.toCharArray()
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ca.sort()
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return String(ca)
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}
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fun isVampiric(n: Long, fl: MutableList<Fangs>): Boolean {
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if (n < 0L) return false
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val len = countDigits(n)
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if (len % 2L == 1L) return false
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val hlen = len / 2
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val first = pow10(hlen - 1)
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val last = 10L * first
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var j: Long
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var cd: Int
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val ss = sortedString(n.toString())
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for (i in first until last) {
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if (n % i != 0L) continue
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j = n / i
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if (j < i) return fl.size > 0
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cd = countDigits(j)
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if (cd > hlen) continue
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if (cd < hlen) return fl.size > 0
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if (ss != sortedString(i.toString() + j.toString())) continue
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if (!(hasTrailingZero(i) && hasTrailingZero(j))) {
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fl.add(Fangs(i, j))
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}
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}
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return fl.size > 0
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}
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fun showFangs(fangsList: MutableList<Fangs>): String {
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var s = ""
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for ((fang1, fang2) in fangsList) {
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s += " = $fang1 x $fang2"
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}
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return s
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}
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fun main(args: Array<String>) {
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println("The first 25 vampire numbers and their fangs are:")
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var count = 0
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var n: Long = 0
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val fl = mutableListOf<Fangs>()
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while (true) {
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if (isVampiric(n, fl)) {
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count++
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println("${"%2d".format(count)} : $n\t${showFangs(fl)}")
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fl.clear()
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if (count == 25) break
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}
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n++
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}
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println()
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val va = longArrayOf(16758243290880L, 24959017348650L, 14593825548650L)
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for (v in va) {
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if (isVampiric(v, fl)) {
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println("$v\t${showFangs(fl)}")
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fl.clear()
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} else {
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println("$v\t = not vampiric")
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}
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}
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}
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