编辑代码

#include <stdio.h>
#include <stdlib.h>

typedef struct {
    int weight;
    int value;
} Item;

// 比较函数，按单位价值降序排列
int compare(const void *a, const void *b) {
    Item *item1 = (Item *)a;
    Item *item2 = (Item *)b;
    double valuePerWeight1 = (double)item1->value / item1->weight;
    double valuePerWeight2 = (double)item2->value / item2->weight;
    return (valuePerWeight2 > valuePerWeight1) - (valuePerWeight1 > valuePerWeight2);
}

// 计算当前节点的界限值
float bound(Item items[], int n, int W, int index, int currWeight, int currValue) {
    if (currWeight >= W) return 0;

    float maxValue = currValue;
    int totWeight = currWeight;

    // 以贪心方式尝试添加剩余物品
    for (int i = index; i < n; i++) {
        if (totWeight + items[i].weight <= W) {
            totWeight += items[i].weight;
            maxValue += items[i].value;
        } else {
            int remain = W - totWeight;
            maxValue += (items[i].value / (float)items[i].weight) * remain;
            break;
        }
    }
    return maxValue;
}

// 分支界限法求解背包问题
int knapsack(Item items[], int n, int W) {
    // 排序物品，按单位价值降序
    qsort(items, n, sizeof(Item), compare);

    // 初始化最大价值
    int maxValue = 0;

    // TODO: 实现分支界限法的具体逻辑
    // 这里需要实现一个优先队列来管理节点，并根据界限值进行搜索

    return maxValue;
}

int main() {
    Item items[] = {{10, 60}, {20, 100}, {30, 120}};
    int W = 50;
    int n = sizeof(items) / sizeof(items[0]);

    printf("最大价值: %d\n", knapsack(items, n, W));
    return 0;
}