Data commit

Task/Superpermutation-minimisation/Zkl/superpermutation-minimisation.zkl

@@ -0,0 +1,36 @@
+const MAX = 12;
+var super=Data(), pos, cnt;  // global state, ick
+
+fcn fact_sum(n){ // -->1! + 2! + ... + n!
+   [1..n].reduce(fcn(s,n){ s + [2..n].reduce('*,1) },0)
+}
+
+fcn r(n){
+   if (not n) return(0);
+
+   c := super[pos - n];
+   if (not (cnt[n]-=1)){
+      cnt[n] = n;
+      if (not r(n-1)) return(0);
+   }
+   super[pos] = c; pos+=1;
+   1
+}
+
+fcn superperm(n){
+   pos = n;
+   len := fact_sum(n);
+   super.fill(0,len);  // this is pretty close to recalloc()
+
+   cnt = (n+1).pump(List()); //-->(0,1,2,3,..n)
+   foreach i in (n){ super[i] = i + 0x31; } //-->"1" ... "123456789:;"
+   while (r(n)){}
+}
+
+foreach n in (MAX){
+   superperm(n);
+   print("superperm(%2d) len = %d".fmt(n,super.len()));
+   // uncomment next line to see the string itself
+   //print(": %s".fmt(super.text));
+   println();
+}