Data commit

Task/Superpermutation-minimisation/Groovy/superpermutation-minimisation.groovy

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+import static java.util.stream.IntStream.rangeClosed
+
+class Superpermutation {
+    final static int nMax = 12
+
+    static char[] superperm
+    static int pos
+    static int[] count = new int[nMax]
+
+    static int factSum(int n) {
+        return rangeClosed(1, n)
+            .map({ m -> rangeClosed(1, m).reduce(1, { a, b -> a * b }) }).sum()
+    }
+
+    static boolean r(int n) {
+        if (n == 0) {
+            return false
+        }
+
+        char c = superperm[pos - n]
+        if (--count[n] == 0) {
+            count[n] = n
+            if (!r(n - 1)) {
+                return false
+            }
+        }
+        superperm[pos++] = c
+        return true
+    }
+
+    static void superPerm(int n) {
+        String chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+        pos = n
+        superperm = new char[factSum(n)]
+
+        for (int i = 0; i < n + 1; i++) {
+            count[i] = i
+        }
+        for (int i = 1; i < n + 1; i++) {
+            superperm[i - 1] = chars.charAt(i)
+        }
+
+        while (r(n)) {
+        }
+    }
+
+    static void main(String[] args) {
+        for (int n = 0; n < nMax; n++) {
+            superPerm(n)
+            printf("superPerm(%2d) len = %d", n, superperm.length)
+            println()
+        }
+    }
+}