Select Code to Download

#!/usr/bin/perl

...
}

printf "Total %d (%d runs)\n", (scalar keys %f), $c;

$ ./derangements.pl 4
2,3,0,1: 11.08% (expected -0.03%)
...
3,2,1,0: 11.13% (expected +0.02%)
3,2,0,1: 11.14% (expected +0.03%)
Total 9 (1000000 runs)