题解 | 二维斐波那契数列

#include <stdio.h>

const int MOD = 1e9 + 7;

int fbn(int n, int m) {
    int a[n + 1][m + 1];
    a[1][1] = 1;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            if (i == 1 && j == 1) {
                continue;
            } else if (j == 1) {
                a[i][j] = a[i - 1][j] % MOD;
            } else if (i == 1) {
                a[i][j] = a[i][j - 1] % MOD;
            } else {
                a[i][j] = (a[i - 1][j] + a[i][j - 1]) % MOD;
            }
        }

    }
    return a[n][m];
}



int main() {
    int n, m;
    scanf("%d %d", &n, &m );
    printf("%d\n", fbn(n, m));


    return 0;
}