hdu 4725 最短路

思路：将每个layer拆成两个点，编号为N+x，和N+N+x。对所有属于layer   x的点i,建N+x到i的有向边，在建i到N+N+x的有向边。最后对所有x号layer和x+1建一条N+N+x到N+x+1的有向边和一条N+N+x+1到N+x的有向边。

#include<set>

#include<cmath>

#include<queue>

#include<cstdio>

#include<vector>

#include<string>

#include<cstdlib>

#include<cstring>

#include<iostream>

#include<algorithm>

#define pb push_back

#define mp make_pair

#define Maxn 300010

#define Maxm 80002

#define LL __int64

#define Abs(x) ((x)>0?(x):(-x))

#define lson(x) (x<<1)

#define rson(x) (x<<1|1)

#define inf 1000000000

#define lowbit(x) (x&(-x))

#define clr(x,y) memset(x,y,sizeof(x))

#define Mod 1000000007

using namespace std;

int head[Maxn],vi[Maxn],e,n,m,c;

int dis[Maxn];

struct Edge{

    int u,v,next;

    int val;

}edge[Maxn*3];

struct Point{

    int id;

    Point (int a){id=a;}

    int operator<(const Point &temp) const{

        return dis[id]>dis[temp.id];

    }

};

priority_queue<Point> q;

void init()

{

    memset(head,-1,sizeof(head));

    memset(vi,0,sizeof(vi));

    e=0;

}

void add(int u,int v,int val)

{

    edge[e].u=u,edge[e].v=v,edge[e].val=val,edge[e].next=head[u],head[u]=e++;

}

void spfa()

{

    int i,j,v,now;

    for(i=0;i<Maxn;i++)

        dis[i]=inf;

    dis[1]=0;

    memset(vi,0,sizeof(vi));

    Point p(0);

    while(!q.empty())

        q.pop();

    q.push(1);

    while(!q.empty()){

        p=q.top();

        now=p.id;

        q.pop();

        if(now==n)

            return ;

        vi[now]=0;

        for(i=head[now];i!=-1;i=edge[i].next){

            v=edge[i].v;

            if(dis[now]+edge[i].val<dis[v]){

                dis[v]=dis[now]+edge[i].val;

                if(!vi[v]){

                    vi[v]=1;

                    q.push(v);

                }

            }

        }

    }

}

int main()

{

    int t,i,j,u,v,val,x,Case=0;

    scanf("%d",&t);

    while(t--){

        init();

        scanf("%d%d%d",&n,&m,&c);

        for(i=1;i<=n;i++){

            scanf("%d",&x);

            add(n+x,i,0);

            add(i,2*n+x,0);

            vi[x]=1;

        }

        for(i=1;i<n;i++){

            if(vi[i]&&vi[i+1]){

                add(2*n+i,n+i+1,c);

                add(2*n+i+1,n+i,c);

            }

        }

        for(i=1;i<=m;i++){

            scanf("%d%d%d",&u,&v,&val);

            add(u,v,val);

            add(v,u,val);

        }

        if(n==0){

            printf("Case #%d: -1\n",++Case);

            continue;

        }

        spfa();

        printf("Case #%d: ",++Case);

        if(dis[n]>=inf)

            printf("-1\n");

        else

            printf("%d\n",dis[n]);

    }

    return 0;

}