优先队列式分支限界法01背包问题c++

以下是使用C++实现优先队列式分支限界法求解0-1背包问题的代码：

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

struct Node {
    int level; // 当前节点所在的层数
    int profit; // 当前节点的价值
    int weight; // 当前节点的重量
    double bound; // 当前节点的价值上界
};

bool operator<(const Node& a, const Node& b) {
    return a.bound < b.bound;
}

double bound(Node u, int n, int W, int* p, int* w) {
    if (u.weight >= W) {
        return 0;
    }
    double bound = u.profit;
    int j = u.level + 1;
    int totweight = u.weight;
    while ((j < n) && (totweight + w[j] <= W)) {
        totweight += w[j];
        bound += p[j];
        j++;
    }
    if (j < n) {
        bound += (W - totweight) * p[j] / w[j];
    }
    return bound;
}

int knapsack(int n, int* p, int* w, int W) {
    priority_queue<Node> Q;
    Node u, v;
    u.level = -1;
    u.profit = 0;
    u.weight = 0;
    u.bound = bound(u, n, W, p, w);
    int maxprofit = 0;
    Q.push(u);
    while (!Q.empty()) {
        u = Q.top();
        Q.pop();
        if (u.bound > maxprofit) {
            v.level = u.level + 1;
            v.weight = u.weight + w[v.level];
            v.profit = u.profit + p[v.level];
            if (v.weight <= W && v.profit > maxprofit) {
                maxprofit = v.profit;
            }
            v.bound = bound(v, n, W, p, w);
            if (v.bound > maxprofit) {
                Q.push(v);
            }
            v.weight = u.weight;
            v.profit = u.profit;
            v.bound = bound(v, n, W, p, w);
            if (v.bound > maxprofit) {
                Q.push(v);
            }
        }
    }
    return maxprofit;
}

int main() {
    int n = 5;
    int p[] = {3, 2, 4, 1, 5};
    int w[] = {2, 1, 3, 2, 4};
    int W = 7;
    int maxprofit = knapsack(n, p, w, W);
    cout << "Max profit: " << maxprofit << endl;
    return 0;
}