Data commit

Task/Vampire-number/Wren/vampire-number.wren

@@ -0,0 +1,73 @@
+import "/fmt" for Fmt
+
+var ndigits = Fn.new { |x|
+    var n = 0
+    while (x > 0) {
+        n = n + 1
+        x = (x/10).floor
+    }
+    return n
+}
+
+var dtally = Fn.new { |x|
+    var t = 0
+    while (x > 0) {
+        t = t + 2.pow((x%10) * 6)
+        x = (x/10).floor
+    }
+    return t
+}
+
+var tens = List.filled(15, 0)
+
+var init = Fn.new  {
+    tens[0] = 1
+    for (i in 1..14) tens[i] = tens[i-1] * 10
+}
+
+var fangs = Fn.new { |x|
+    var f = []
+    var nd = ndigits.call(x)
+    if ((nd&1) == 1) return f
+    nd = (nd/2).floor
+    var lo = tens[nd-1].max(((x + tens[nd] - 2) / (tens[nd] - 1)).floor)
+    var hi = (x/lo).floor.min(x.sqrt.floor)
+    var t = dtally.call(x)
+    var a = lo
+    while (a <= hi) {
+        var b = (x/a).floor
+        if (a*b == x && ((a%10) > 0 || (b%10) > 0) && t == dtally.call(a) + dtally.call(b)) {
+            f.add(a)
+        }
+        a = a + 1
+    }
+    return f
+}
+
+var showFangs = Fn.new { |x, f|
+    Fmt.write("$6d", x)
+    if (f.count > 1) System.print()
+    for (a in f) Fmt.print(" = $3d x $3d", a, (x/a).floor)
+}
+
+init.call()
+var x = 1
+var n = 0
+while (n < 25) {
+    var f = fangs.call(x)
+    if (f.count > 0) {
+        n = n + 1
+        Fmt.write("$2d: ", n)
+        showFangs.call(x, f)
+    }
+    x = x + 1
+}
+System.print()
+for (x in [16758243290880, 24959017348650, 14593825548650]) {
+    var f = fangs.call(x)
+    if (f.count > 0) {
+        showFangs.call(x, f)
+    } else {
+        Fmt.print("$d is not vampiric", x)
+    }
+}