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
",pqspfa(1,n));
return 0;
}
</span>