C++ Knapsack Algorithm Implementation - c++

Question

My algorithm for the best-first, branch and bound knapsack problem is giving me a max profit of 80 when it should be 90. I'm wondering where I went wrong... my thinking is the priority queue is a bit off.
Given input:
4,16 // 4 items to follow , 16 capacity knapsack
2,40 // item1.. weighs 2, costs 40
5,30 // item2.. weighs 5, costs 30
10,50 // item3.. weighs 10, costs 50
5,10 // item4.. weighs 5, costs 10
Code:
#include <iostream>
#include <string>
#include <queue>
#include <utility>
typedef struct node{
int level;
int profit;
int weight;
int bound;
} node;
struct node_cmp{
bool operator()(const node& a, const node& b) const{
return a.bound < b.bound;
}
};
int KWF2(int i, int weight, int profit, int *w, int *p, int C, int n){
int weight1 = weight;
int bound = profit;
int j;
float x[n+1];
for(j = i; j <= n; j++){
x[j] = 0;
}
while(weight1 < C && (i <= n)){
if(weight1 + w[i] <= C){
x[i] = 1;
weight1 += w[i];
bound += p[i];
}
else{
x[i] = ((float)C-(float)weight1)/(float)w[i];
weight1 = C;
bound = bound + p[i] * x[i];
}
i++;
}
return bound;
}
void knapsack(int *w, int *p, int C, int maxprofit, int n){
int maxp = maxprofit;
std::priority_queue<node,std::vector<node>,node_cmp> PQ;
node u,v;
v.level = 0;
v.profit = 0;
v.weight = 0;
v.bound = KWF2(v.level+1,v.weight,v.profit,w,p,C,n);
PQ.push(v);
while(!PQ.empty()){
v = PQ.top();
PQ.pop();
if(v.bound > maxp){
u.level = v.level + 1;
//yes child
u.weight = v.weight + w[u.level];
u.profit = v.profit + p[u.level];
if((u.weight <= C) && (u.profit > maxp)){
maxp = u.profit;
}
if(KWF2(u.level+1,u.weight,u.profit,w,p,C,n) > maxp){
PQ.push(u);
}
//no child
u.weight = v.weight;
u.profit = v.profit;
u.bound = KWF2(u.level+1,u.weight,u.profit,w,p,C,n);
if(u.bound > maxp){
PQ.push(u);
}
}
}
printf("%d\n",maxp);
}
int main(int argc, char **argv){
int n,C;
FILE *in = fopen(argv[1],"r");
fscanf(in,"%d,%d",&n,&C);
int w[n+1];
int p[n+1];
float ratio[n+1];
for(int i = 0; i < n; i++){
fscanf(in,"%d,%d",&w[i+1],&p[i+1]);
ratio[i+1] = (float)p[i+1]/(float)w[i+1];
}
int temp_w,temp_p;
float temp_r;
for(int i = 1; i <= n; i++){
for(int j = i + 1; j <= n; j++){
if(ratio[i] < ratio[j]){
temp_w = w[i];
temp_p = p[i];
temp_r = ratio[i];
w[i] = w[j];
p[i] = p[j];
ratio[i] = ratio[j];
w[j] = temp_w;
p[j] = temp_p;
ratio[j] = ratio[i];
}
}
}
int maxprofit = 0;
knapsack(w,p,C,maxprofit,n);
fclose(in);
return 0;
}