Data commit

Task/Vampire-number/Kotlin/vampire-number.kotlin

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