{-

- Solution to Project Euler problem 15

- Copyright (c) Project Nayuki. All rights reserved.

-

- https://www.nayuki.io/page/project-euler-solutions

- https://github.com/nayuki/Project-Euler-solutions

-}

import qualified EulerLib

-- This is a classic combinatorics problem. To get from the top left corner to the bottom right corner of an N*N grid,

-- it involves making exactly N moves right and N moves down in some order. Because each individual down or right move

-- is indistinguishable, there are exactly 2N choose N (binomial coefficient) ways of arranging these moves.

main = putStrLn (show ans)

ans = EulerLib.binomial 40 20