题解 | 二维斐波那契数列

n, m = map(int,input().split())
dp = [[0]*(m+1) for _ in range(n+1)]
if m==1 or n==1:
    print(1)
else:
    for i in range(1,n+1):
        for j in range(1,m+1):
            if i==1 or j==1:
                dp[i][j] = 1
            else:
                dp[i][j] = dp[i-1][j]+dp[i][j-1]
    print(dp[n][m]%(7+10**9))