Experiments in Constraint Driven Programming
Download and Install: http://labix.org/python-constraint
$ time python3 8queens_backtrack.py | wc -l
14200
real 0m14.089s
user 0m14.071s
sys 0m0.020s
$ time python3 8queens.py | wc -l
14200
real 0m22.480s
user 0m22.396s
sys 0m0.058s