June 2018 Update

Task/Subtractive-generator/Kotlin/subtractive-generator.kotlin

@@ -0,0 +1,40 @@
+// version 1.1.51
+
+const val MOD = 1_000_000_000
+
+val state = IntArray(55)
+var si = 0
+var sj = 0
+
+fun subrandSeed(p: Int) {
+    var p1 = p
+    var p2 = 1
+    state[0] = p1 % MOD
+    var j = 21
+    for (i in 1..54) {
+        if (j >=55) j -= 55
+        state[j] = p2
+        p2 = p1 - p2
+        if (p2 < 0) p2 += MOD
+        p1 = state[j]
+        j += 21
+    }
+    si = 0
+    sj = 24
+    repeat(165) { subrand() }
+}
+
+fun subrand(): Int {
+    if (si == sj) subrandSeed(0)
+    if (si-- == 0) si = 54
+    if (sj-- == 0) sj = 54
+    var x = state[si] - state[sj]
+    if (x < 0) x += MOD
+    state[si] = x
+    return x
+}
+
+fun main(args: Array<String>) {
+    subrandSeed(292_929)
+    for (i in 0..9) println("r[${i + 220}] = ${subrand()}")
+}