题解 | #走方格的方案数#Combination nCr n选r Combination

画了一下图找到规律就是nCr种走法，跟排列组合是一样的

import math as m

while 1:
    try:
        a,b = [int(x) for x in input().split()]
        n = a+b 
        r = a
        r = int(m.factorial(n)/(m.factorial(n-r)*m.factorial(r)))
        print(r)
    except:
        break