- 問題
Problem 15:Lattice paths
Starting in the top left corner of a 2×2 grid, and only being able to move to the right and down, there are exactly 6 routes to the bottom right corner.How many such routes are there through a 20×20 grid?
- 解答例
import math print(math.factorial(40) // math.factorial(20) // math.factorial(20))