poj 1724 有限制条件的最短路

#include<iostream>
#include<queue>
#include<cstring>
#include<functional>
using namespace std;
#define MAX_INT 1234567890
struct node
{
int v;
int length;
int value;
int next;
};
node edge[10001];
int head[101];
struct Node
{
int v,dist,cost;
friend bool operator < (const Node a,const Node b)
{
if(a.dist==b.dist)
return a.cost>b.cost;
return a.dist>b.dist;
}
};
priority_queue<Node> Q;
int pfs(int n,int coin)
{
int j,s,k=0;
Node e={1,0,0};
Q.push(e);
while(!Q.empty())
{
e=Q.top(),Q.pop();
if(e.v==n) { k=e.dist; break;}
for(j=head[e.v];j;j=edge[j].next)
{
s=edge[j].v;
if(e.cost+edge[j].value<=coin)
{
Node e1={ s,e.dist+edge[j].length,e.cost+edge[j].value};
Q.push(e1);
}
}
}
while(!Q.empty()) Q.pop();
return k;
}
int main()
{
int i,k,m,n,coin,N,source,destination,length,value;
while(cin>>coin>>n>>m)
{
memset(head,0,sizeof(head));
for(N=1,i=0;i<m;i++)
{
cin>>source>>destination>>length>>value;
if(source==destination) continue;
node e={destination,length,value,N};
edge
=e;
edge
.next=head[source];
head[source]=N++;
}
k=pfs(n,coin);
if(k==0)
cout<<"-1"<<endl;
else
cout<<k<<endl;
}
return 0;
}