Data commit

Task/Superpermutation-minimisation/Julia/superpermutation-minimisation.julia

@@ -0,0 +1,40 @@
+const nmax = 12
+
+function r!(n, s, pos, count)
+    if n == 0
+        return false
+    end
+    c = s[pos + 1 - n]
+    count[n + 1] -= 1
+    if count[n + 1] == 0
+        count[n + 1] = n
+        if r!(n - 1, s, pos, count) == 0
+            return false
+        end
+    end
+    s[pos + 1] = c
+    pos += 1
+    true
+end
+
+function superpermutation(n)
+    count = zeros(nmax)
+    pos = n
+    superperm = zeros(UInt8, n < 2 ? n : mapreduce(factorial, +, 1:n))
+    for i in 0:n-1
+        count[i + 1] = i
+        superperm[i + 1] = Char(i + '0')
+    end
+    count[n + 1] = n
+    while r!(n, superperm, pos, count) ; end
+    superperm
+end
+
+function testsuper(N, verbose=false)
+    for i in 0:N-1
+        s = superpermutation(i)
+        println("Superperm($i) has length $(length(s)) ", (verbose ? String(s) : ""))
+    end
+end
+
+testsuper(nmax)