// http://shootout.alioth.debian.org/debian/benchmark.php?test=fannkuch&lang=all#about

/ permutations of x
p:{:[1<x;,/(>:'(x,x)#1,x#0)[;0,'1+_f x-1];,!x]}

/ fannkuch
F:0;f:{G::0;{G+:1;@[x;i;:;|x i:!*x]}/x;F|:G-1}

\t f'1+p 10
F