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;
}