不多说了，就是裸的模版题。

贴代码：

<span style="font-family:KaiTi_GB2312;font-size:18px;">#include <queue>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#define N 30500
#define M 200000
#define inf 0x3f3f3f3f
using namespace std;
struct KSD
{
	int v,len,next;
}e[M];
int head[N],cnt;
void add(int u,int v,int len)
{
	cnt++;
	e[cnt].v=v;
	e[cnt].len=len;
	e[cnt].next=head[u];
	head[u]=cnt;
}
struct Lux
{
	int f,v;
	bool operator < (const Lux &a)const
	{return f>a.f;}
	Lux(){}
	Lux(int _f,int _v):f(_f),v(_v){}
};
int dist[N];
bool in[N];
int pqspfa(int s,int t)
{
	priority_queue<Lux>pq;
	int i,u,v;
	memset(dist,0x3f,sizeof(dist));
	dist[s]=0;
	in[s]=1;
	pq.push(Lux(0,s));
	while(!pq.empty())
	{
		Lux U=pq.top();pq.pop();
		u=U.v;
		in[u]=0;
		for(i=head[u];i;i=e[i].next)
		{
			v=e[i].v;
			if(dist[v]>dist[u]+e[i].len)
			{
				dist[v]=dist[u]+e[i].len;
				if(!in[v])
				{
					in[v]=1;
					pq.push(Lux(dist[v],v));
				}
			}
		}
	}
	return dist[t];
}
int n,m;
int main()
{
//	freopen("test.in","r",stdin);
	int i,j,k;
	int a,b,c;
	scanf("%d%d",&n,&m);
	for(i=1;i<=m;i++)
	{
		scanf("%d%d%d",&a,&b,&c);
		add(a,b,c);
	}
	printf("%d\n",pqspfa(1,n));
	return 0;
}
</span>

【POJ3159】Candies 裸的pqspfa模版题