! Copyright (c) 2007 Aaron Schaefer. ! See http://factorcode.org/license.txt for BSD license. USING: kernel math math.combinatorics project-euler.common ; IN: project-euler.015 ! http://projecteuler.net/index.php?section=problems&id=15 ! DESCRIPTION ! ----------- ! Starting in the top left corner of a 2x2 grid, there are 6 routes (without ! backtracking) to the bottom right corner. ! How many routes are there through a 20x20 grid? ! SOLUTION ! -------- : euler015 ( -- answer ) 20 grid-paths ; ! [ euler015 ] 100 ave-time ! 0 ms ave run time - 0.2 SD (100 trials) SOLUTION: euler015