题解 | 二维斐波那契数列

import java.util.Scanner;

public class Main {
    static final int MOD = 1000000007;
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int m = scanner.nextInt();
        
        long[][] dp = new long[n + 1][m + 1];
        
        for (int i = 1; i <= n; i++)
        {
            dp[i][1] = 1;
        }
        for (int j = 1; j <= m; j++)
        {
            dp[1][j] = 1;
        }
        
        for (int i = 2; i <= n; i++)
        {
            for (int j = 2; j <= m; j++)
            {
                dp[i][j] = (dp[i - 1][j] + dp[i][j - 1]) % MOD;
            }
        }
        System.out.println(dp[n][m]);
    }
}