使用BufferedReader与BufferedWriter是习惯，在输入输出数据不那么大的时候可以使用Scanner与sout替换

视频中的一维版代码

import java.io.*;
public class Main {
        public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));
        String[] temp = reader.readLine().split(" ");
        int n1 = Integer.parseInt(temp[0]), n2 = Integer.parseInt(temp[1]), m = Integer.parseInt(temp[2]);
        int mod = (int) 1e9+7; int[] f = new int[100010];

        f[0] = 1;
        temp = reader.readLine().split(" ");
        for (int i = 1; i <= n1; i++) {
            int p = Integer.parseInt(temp[i-1]);
            for (int j = p; j <= m; j++) {
                f[j] = ( f[j] + f[j-p] ) % mod;
            }
        }
        temp = reader.readLine().split(" ");
        for (int i = 1; i <= n2; i++) {
            int p = Integer.parseInt(temp[i-1]);
            for (int j = m; j >= p; j--) {
                f[j] = ( f[j] + f[j-p] ) % mod;
            }
        }
        System.out.println(f[m]);
    }
}

二维版代码

public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));
        String[] p = reader.readLine().split(" ");
        int n1 = Integer.parseInt(p[0]), n2 = Integer.parseInt(p[1]), m = Integer.parseInt(p[2]);

        int mod = (int) 1e9+7;
        //f[i][j] 表示的对于前i种硬币，需要凑出的数值为j时的选法数量。
        int[][] f = new int[n1+n2+1][m+1];
        for (int i = 1; i <= n1+n2; i++) {
            //对于前i种硬币，总面值为0时只有一种选法
            f[i][0] = 1;
        }
        p = reader.readLine().split(" ");
        for (int i = 1; i <= n1; i++) {
            int P = Integer.parseInt(p[i-1]);
            //因为j=0时无论有几种硬币可以选，答案都是1，所以这里跳过，下同。
            for (int j = 1; j <= m; j++) {
                if (j >= P){
                    f[i][j] = (f[i-1][j] + f[i][j-P]) % mod;
                }else{
                    f[i][j] = f[i-1][j];
                }
            }
        }
        p = reader.readLine().split(" ");
        for (int i = n1 + 1; i <= n1+n2; i++) {
            int P = Integer.parseInt(p[i-n1-1]);
            for (int j = 1; j <= m; j++) {
                if (j >= P){
                    f[i][j] = (f[i-1][j] + f[i-1][j-P]) % mod;
                }else{
                    f[i][j] = f[i-1][j];
                }

            }
        }
        System.out.println(f[n1+n2][m]);
    }