Java对01背包的简单实现与解集的输出

package com.xiejianjun.day12;

import java.util.Arrays;



public class _01Backpack {
    //物品质量
    private final int[] w = {1, 4, 3};
    //物品价值
    private final int[] v = {1500, 3000, 2000};
    //背包容量
    private final int backpackV = 4 ;
    //总价值二维数组
    private int[][] dp;

    public void displayDpArr() {
        if (dp == null) return;
        for (int[] ints : dp) {
            System.out.println(Arrays.toString(ints));
        }
        int i = dp.length - 1;
        int j = dp[0].length - 1;
        while (i > 0) {
            // if (result[i][j] == 1) {
            if (dp[i][j] != dp[i - 1][j]) {
                System.out.println("序号" + i + "的物品已放入背包中");
                j -= w[i - 1];
            }
            else {
                System.out.println("序号" + i + "的物品未放入背包中");
            }
            i--;

        }
    }

    public void getDp() {
        init();



        for (int i = 1; i <= w.length; i++) {
            for (int j = 0; j < backpackV + 1; j++) {
                if (w[i - 1] > j) {
                    dp[i][j] = dp[i - 1][j];
                } else {
                    dp[i][j] = Math.max(dp[i - 1][j], dp[i - 1][j - w[i - 1]] + v[i - 1]);
                }
            }
        }
    }

    private void init() {
        this.dp = new int[w.length + 1][backpackV + 1];
        for (int i = 0; i < w.length + 1; i++) {
            for (int j = 0; j < backpackV + 1; j++) {
                dp[i][j] = 0;
            }
        }
    }

    public static void main(String[] args) {
        _01Backpack backpack = new _01Backpack();
        backpack.getDp();
        backpack.displayDpArr();
    }


}