贪心法解决0_1背包问题

源代码：

#include <iostream>
#define BACKSIZE 50.0
using namespace std;

struct node
{
    float weight;
    float value;
    float average_value;
    int index;
};

int main()
{
    int n;
    cout << "请输入物体的数量：" << endl;
    cin >> n;
    node *  o = new node [n];
    for (int i = 0; i < n; i++)
    {
        float w, v;
        cout << "请输入第" << i + 1 << "个物品的重量：" << endl;
        cin >> w;
        cout << "请输入第" << i + 1 << "个物品的价值：" << endl;
        cin >> v;
        o[i].weight = w;
        o[i].value = v;
        o[i].average_value = v / w;
        o[i].index = i + 1;
    }

    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n - i; j++)
        {
            if (o[j].average_value < o[j + 1].average_value)
            {
                float tempw = o[j].weight;
                o[j].weight = o[j + 1].weight;
                o[j + 1].weight = tempw;

                float tempav =o[j].average_value;
                o[j].average_value = o[j + 1].average_value;
                o[j + 1].average_value = tempav;

                float tempi = o[j].index;
                o[j].index = o[j + 1].index;
                o[j + 1].index = tempi;
            }
        }
    }

    float total = 0.0;
    int mark;
    for (int i = 0; i < n; i++)
    {
        total += o[i].weight;
        if (total <= BACKSIZE)
        {
            mark = i + 1;
        }
    }

    cout << "背包可以放下以下几个物体：" << endl;
    for (int i = 0; i < mark; i++)
    {
        cout << "第" << o[i].index << "个物体" << endl;
    }

    delete [] o;

    return 0;
}

运行结果截图：