使用c++语言解决背包问题贪心法

以下是使用C++语言解决背包问题的贪心算法：

#include <iostream>
#include <algorithm>
using namespace std;

struct Item {
    int value;
    int weight;
};

bool cmp(Item a, Item b) {
    double r1 = (double)a.value / a.weight;
    double r2 = (double)b.value / b.weight;
    return r1 > r2;
}

double fractionalKnapsack(int W, Item arr[], int n) {
    sort(arr, arr + n, cmp);
    int curWeight = 0;
    double finalValue = 0.0;
    for (int i = 0; i < n; i++) {
        if (curWeight + arr[i].weight <= W) {
            curWeight += arr[i].weight;
            finalValue += arr[i].value;
        } else {
            int remain = W - curWeight;
            finalValue += arr[i].value * ((double) remain / arr[i].weight);
            break;
        }
    }
    return finalValue;
}

int main() {
    int W = 50;
    Item arr[] = {{60, 10}, {100, 20}, {120, 30}};
    int n = sizeof(arr) / sizeof(arr[0]);
    cout << "Maximum value we can obtain = "
         << fractionalKnapsack(W, arr, n);
    return 0;
}