Data commit

Task/Superpermutation-minimisation/Nim/superpermutation-minimisation.nim

@@ -0,0 +1,44 @@
+import strformat
+
+const MAX = 12
+
+var super: seq[char] = @[]
+var pos: int
+var cnt: array[MAX, int]
+
+proc factSum(n: int): int =
+  var s, x = 0
+  var f = 1
+  while x < n:
+    inc x
+    f *= x
+    inc s, f
+  s
+
+proc r(n: int): bool =
+  if n == 0:
+    return false
+  var c = super[pos - n]
+  dec cnt[n]
+  if cnt[n] == 0:
+    cnt[n] = n
+    if not r(n - 1):
+      return false
+  super[pos] = c
+  inc pos
+  true
+
+proc superperm(n: int) =
+  pos = n
+  var le = factSum(n)
+  super.setLen(le)
+  for i in 0..n:
+    cnt[i] = i
+  for i in 1..n:
+    super[i-1] = char(i + ord('0'))
+  while r(n):
+    discard
+for n in 0..<MAX:
+  write(stdout, fmt"superperm({n:2})")
+  superperm(n)
+  writeLine(stdout, fmt" len = {len(super)}")