HDU 1009 The Shortest Path in Nya Graph

　　迪杰斯特拉 + 优先队列

　　

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <queue>
#include <vector>

#define LL __int64

const LL INF = 2000000000;

using namespace std;

LL dis[300100];

int head[300100];

struct E
{
    int u,v,w,next;
}edge[1001000];

int top;

void link(int u,int v,int w)
{
    edge[top].u = u;
    edge[top].v = v;
    edge[top].w = w;
    edge[top].next = head[u];
    head[u] = top++;
}

struct HeapNode
{
    int d,u;
    bool operator < (const HeapNode& rhs) const{
        return d>rhs.d;
    }
};

void dij(int st,int n)
{
    priority_queue<HeapNode> q;

    HeapNode p;

    p.d = 0;
    p.u = 1;

    q.push(p);

    while(q.empty() == false)
    {
        HeapNode x = q.top();
        q.pop();

        int u = x.u;

        st = head[u];

        while(st != -1)
        {
            if(dis[u] + edge[st].w < dis[edge[st].v])
            {
                dis[edge[st].v] = edge[st].w + dis[u];

                HeapNode temp;

                temp.d = dis[edge[st].v];
                temp.u = edge[st].v;
                q.push(temp);
            }
            st = edge[st].next;

        }
    }

    if(dis[n] == INF)
        cout<<"-1"<<endl;
    else
        cout<<dis[n]<<endl;
}

int main()
{
    int i,n,m,c,u,v,w;
    int T,icase = 0;

    cin>>T;
    while(T--)
    {
        scanf("%d %d %d",&n,&m,&c);

        memset(head,-1,(n*3+2)*sizeof(int));

        top = 0;

        for(i = 1;i <= n; ++i)
        {
            scanf("%d",&u);

            link(n+2*u-1,i,0);
            link(i,n+u*2,0);
        }

        for(i = 1;i < n; ++i)
        {
            link(n+i*2+2,n+i*2-1,c);
            link(n+i*2,n+i*2+1,c);
        }

        for(i = 1;i <= m; ++i)
        {
            scanf("%d %d %d",&u,&v,&w);
            link(u,v,w);
            link(v,u,w);
        }

        for(i = 1,n *= 3;i <= n; ++i)
        {
            dis[i] = INF;
        }

        dis[1] = 0;

        printf("Case #%d: ",++icase);
        dij(1,n/3);

    }
    return 0;
}

　　墨迹了一下午 效率低了一13