使用分支定界法的 0/1 背包的以下代码显示了错误：
第 15 行：“项目”无法启动参数声明。第 15 行：) 预期。对于函数绑定也观察到相同的情况。
#include <stdio.h>
#include<conio.h>
typedef enum {false, true}bool;
struct Item
{
float weight;
int value;
};
struct Node
{
int level, profit, bound;
float weight;
};
bool cmp(Item a, Item b)
{
double r1 = (double)a.value / a.weight;
double r2 = (double)b.value / b.weight;
return r1 > r2;
}
int bound(Node u, int n, int W, Item arr[])
{
if (u.weight >= W)
return 0;
int profit_bound = u.profit;
int j = u.level + 1;
int totweight = u.weight;
while ((j < n) && (totweight + arr[j].weight <= W))
{
totweight += arr[j].weight;
profit_bound += arr[j].value;
j++;
}
if (j < n)
profit_bound += (W - totweight) * arr[j].value /
arr[j].weight;
return profit_bound;
}
int knapsack(int W, Item arr[], int n)
{
sort(arr, arr + n, cmp);
queue<Node> Q;
Node u, v;
u.level = -1;
u.profit = u.weight = 0;
Q.push(u);
int maxProfit = 0;
while (!Q.empty())
{
u = Q.front();
Q.pop();
if (u.level == -1)
v.level = 0;
if (u.level == n-1)
continue;
v.level = u.level + 1;
v.weight = u.weight + arr[v.level].weight;
v.profit = u.profit + arr[v.level].value;
if (v.weight <= W && v.profit > maxProfit)
maxProfit = v.profit;
v.bound = bound(v, n, W, arr);
if (v.bound > maxProfit)
Q.push(v);
v.weight = u.weight;
v.profit = u.profit;
v.bound = bound(v, n, W, arr);
if (v.bound > maxProfit)
Q.push(v);
}
return maxProfit;
}
void main()
{
int W = 10; // Weight of knapsack
Item arr[] = {{2, 40}, {3.14, 50}, {1.98, 100},
{5, 95}, {3, 30}};
int n = sizeof(arr) / sizeof(arr[0]);
printf("Maximum possible profit =%d " ,knapsack(W, arr, n));
getch();
}