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K短路 存模板

#include <cstdio>
#include <queue>
#include <cstring>
#include <algorithm>
using namespace std;
#define N 0x3f3f3f3f

int dis[1010];

struct node1
{
    int v;
    int w;
    int next;
};

struct node2
{
    bool operator < (const node2 &rhs) const
    {
        return val + dis[id] > rhs.val + dis[rhs.id];
    }
    int id;
    int val;
};

priority_queue <node2> que;
node1 edge1[200010],edge2[200010];
int first1[1010],first2[1010],book[1010];
int n,m,num,s,e,k;

void addedge(node1* edge,int* first,int u,int v,int w)
{
    edge[num].v=v;
    edge[num].w=w;
    edge[num].next=first[u];
    first[u]=num++;
    return;
}

void dijkstra()
{
    node2 cur,tem;
    int i,u,v,w;
    while(!que.empty()) que.pop();
    memset(dis,0x3f,sizeof(dis));
    memset(book,0,sizeof(book));
    tem.id=e,tem.val=0;
    que.push(tem);
    dis[e]=0;
    while(!que.empty())
    {
        cur=que.top();
        que.pop();
        u=cur.id;
        if(book[u]) continue;
        book[u]=1;
        for(i=first2[u];i!=-1;i=edge2[i].next)
        {
            v=edge2[i].v,w=edge2[i].w;
            if(!book[v]&&dis[v]>dis[u]+w)
            {
                dis[v]=dis[u]+w;
                tem.id=v,tem.val=dis[v];
                que.push(tem);
            }
        }
    }
    return;
}

int astar()
{
    node2 cur,tem;
    int i,u,v,w;
    while(!que.empty()) que.pop();
    tem.id=s,tem.val=0;
    que.push(tem);
    k--;
    while(!que.empty())
    {
        cur=que.top();
        que.pop();
        u=cur.id;
        if(u==e)
        {
            if(k>0) k--;
            else return cur.val;
        }
        for(i=first1[u];i!=-1;i=edge1[i].next)
        {
            v=edge1[i].v,w=edge1[i].w;
            tem.id=v,tem.val=cur.val+w;
            que.push(tem);
        }
    }
    return -1;
}

int main()
{
    int i,u,v,w;
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        memset(first1,-1,sizeof(first1));
        memset(first2,-1,sizeof(first2));
        num=0;
        for(i=1;i<=m;i++)
        {
            scanf("%d%d%d",&u,&v,&w);
            addedge(edge1,first1,u,v,w);
            addedge(edge2,first2,v,u,w);
        }
        scanf("%d%d%d",&s,&e,&k);
        dijkstra();
        if(dis[s]==N)
        {
            printf("-1\n");
            continue;
        }
        if(s==e) k++;
        printf("%d\n",astar());
    }
    return 0;
}