dfs方法

import java.util.*;
import java.io.*;

public class Main {
    static final int N = 20;
    static int[][] f = new int[N][N], v = new int[N][N], w = new int[N][N];
    static ArrayList<int[]> ans = new ArrayList<>();
    static PrintWriter out = new PrintWriter(System.out);
    static int n, m;

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        String[] str = sc.nextLine().split(" ");
        n = Integer.parseInt(str[0]);
        m = Integer.parseInt(str[1]);

        for (int i = 1; i <= n; i++) {
            str = sc.nextLine().split(" ");
            for (int j = 1; j <= m; j++) {
                v[i][j] = j;
                w[i][j] = Integer.parseInt(str[j - 1]);
            }
        }

        for (int i = 1; i <= n; i++)
            for (int j = 1; j <= m; j++) {
                f[i][j] = f[i - 1][j];
                for (int k = 1; k <= v[i][k] && v[i][k] <= j; k++)
                    f[i][j] = Math.max(f[i][j], f[i - 1][j - v[i][k]] + w[i][k]);
            }

        out.println(f[n][m]);
        for (int i = 1; i <= n; i++) ans.add(new int[]{i, 0});//可能出现没有分配的情况

        dfs(n, m);
        ans.sort((o1, o2) -> o1[0] - o2[0]);//排序或者倒着输出
        for (int[] item : ans) out.println(item[0] + " " + item[1]);
        out.flush();
    }

    static void dfs(int i, int j) {
        if (i <= 0 || j < 0) return;

        if (f[i][j] == f[i - 1][j]) dfs(i - 1, j);
        else {
            for (int k = 1; k <= v[i][k] && v[i][k] <= j; k++) {
                if (f[i][j] == f[i - 1][j - v[i][k]] + w[i][k]) {
                    ans.set(i - 1, new int[]{i, k});
                    dfs(i - 1, j - v[i][k]);//这里注意一下索引的偏移即可
                    return;
                }
            }
        }
    }
}