题解 | 二维斐波那契数列

n, m = map(int, input().split())

a = [[0] * m for _ in range(n)]

for i in range (n):
    for j in range(m):
        if i == 0 and j == 0:
            a[i][j] = 1
        elif i == 0:
            a[i][j] = a[i][j-1]
        elif j == 0:
            a[i][j] = a[i-1][j]
        else:
            a[i][j] = a[i-1][j] + a[i][j-1]

print(a[n-1][m-1] % (10 ** 9 + 7))