// This can be run using Cintcode BCPL freely available from www.cl.cam.ac.uk/users/mr10.

GET "libhdr.h"

GLOBAL { count:ug; all  }

LET try(ld, row, rd) BE TEST row=all

                        THEN count := count + 1

                        ELSE { LET poss = all & ~(ld | row | rd)
                               WHILE poss DO
                               { LET p = poss & -poss
                                 poss := poss - p
                                 try(ld+p << 1, row+p, rd+p >> 1)
                               }
                             }

LET start() = VALOF
{ all := 1

  FOR i = 1 TO 16 DO
  { count := 0
    try(0, 0, 0)
    writef("Number of solutions to %i2-queens is %i7*n", i, count)
    all := 2*all + 1
  }

  RESULTIS 0
}