题解 | 二维斐波那契数列

#include <stdio.h>

int main() {
	int n = 0;
	int m = 0;
	scanf("%d %d", &n, &m);
	long long arr[877][877] = { 1 };
	long long sum = 1;
	if (n >= 2 && m >= 2) {
		for (int i = 1; i < n; i++) {
			arr[i][0] = 1;
			for (int j = 1; j < m; j++) {
				arr[0][j] = 1;
				arr[i][j] = (arr[i - 1][j] + arr[i][j - 1]) % 1000000007;
				sum = arr[i][j];
			}
		}
	}
	printf("%lld", sum);
	return 0;
}