Dijkstra算法之六----邻接链表+优先队列实现Dijkstra算法

//poj 1511 Invitation Cards

#include<iostream>        //Dijkstra+邻接链表+优先队列        1735MS!
#include<queue>
#define maxn 1000002
using namespace std;
struct Edge 
{
    int v; 
    int weight;
    int next;
}Vertex[maxn];
int head[maxn],curr;                            
const __int64 inf=(__int64)1<<63-1;            
int cases,p,e,i,j,edge[maxn][3];
void graph(int tag)
{
    int u,v,w;
    curr=0;
    memset(head,-1,sizeof(head[0])*(p+1));
    for(i=1;i<=e;++i)
    {
        u=edge[i][0];v=edge[i][1];w=edge[i][2];
        if(tag)
            swap(u,v);
        Vertex[curr].v=v;
        Vertex[curr].weight=w;
        Vertex[curr].next=head[u];
        head[u]=curr++;
    }
}
struct Dis
{
    int v,dis;
    bool operator<(const Dis &a)const
    {
        return dis>a.dis;
    }
};
__int64 distD[maxn],sum;
void Dijkstra(int u)    
{
    fill(distD,distD+p+1,inf);
    distD[u]=0;
    Dis fro,tmp;
    fro.v=u;fro.dis=0;
    priority_queue<Dis> col;
    col.push(fro);
    while(!col.empty())
    {
        fro=col.top();
        col.pop();
        if(distD[fro.v]<fro.dis)
            continue;
        for(i=head[fro.v];i!=-1;i=Vertex[i].next)
            if(  distD[fro.v]+Vertex[i].weight < distD[Vertex[i].v] )
            {
                distD[Vertex[i].v]=distD[fro.v]+Vertex[i].weight;
                tmp.v=Vertex[i].v;tmp.dis=distD[Vertex[i].v];
                col.push(tmp);
            }
    }
    for(i=2;i<=p;++i)
        sum+=distD[i];
}
int main()
{
    scanf("%d",&cases);
    while(cases--)
    {
        scanf("%d%d",&p,&e);
        sum=0;
        for(i=1;i<=e;++i)
            scanf("%d%d%d",&edge[i][0],&edge[i][1],&edge[i][2]);
        graph(0);
        Dijkstra(1);
        graph(1);
        Dijkstra(1);
        printf("%I64d\n",sum);
    }
    return 0;
}