K最短路 A*算法

POJ2449 Remmarguts' Date

 #include <iostream>
 #include <algorithm>
 #include <queue>
 #include <stdio.h>
 using namespace std;
 int m,n,s,t,k;
 #define M 100005
 #define N 1005
 #define INF 100000000
 int dis[N];
 struct edge
 {
     int v,val,next;//边的终点，边权
     edge(){}
     edge(int _v,int _val,int _next){v=_v,val=_val,next=_next;}
 }line[M],_line[M];
 int head[M],_head[M];

 struct dijnode
 {
     int v,dis;
     dijnode(){}
     dijnode(int _v,int _dis){v=_v,dis=_dis;}
     friend bool operator <(const dijnode &a,const dijnode &b)
     {
         return a.dis>b.dis;
     }
 };
 struct Anode
 {
     int v,g,h;//v:当前点 g:起点到点v距离 h:点v到终点距离
     Anode(){}
     Anode(int _v,int _g,int _h){v=_v,g=_g;h=_h;}
     friend bool operator <(const Anode&a,const Anode&b)
     {
         return a.h+a.g>b.h+b.g;
     }
 };
 void input(){
     memset(head,-,sizeof(head));
     memset(_head,-,sizeof(_head));
     int u,v,val;
     int e=,_e=;
     for(int i=;i<m;i++)
     {
         scanf("%d%d%d",&u,&v,&val);
         line[e]=edge(v,val,head[u]);
         head[u]=e++;
         _line[_e]=edge(u,val,head[v]);
         _head[v]=_e++;
     }
 }
 int vis[N];
 void dijkstra()
 {
     memset(vis,,sizeof(vis));
     priority_queue<dijnode>pq;
     for(int i=;i<n;i++)
         dis[i]=INF;

     dijnode node =dijnode(t,);
     dis[t]=;
     pq.push(node);

     while(!pq.empty())
     {
         dijnode tmp = pq.top();
         pq.pop();

         if(vis[tmp.v])continue;
         vis[tmp.v]=;
         for(int i=_head[tmp.v];i!=-;i=_line[i].next)
         {
             if(tmp.dis+_line[i].val<dis[_line[i].v])
             {
                 dis[_line[i].v]=tmp.dis+_line[i].val;
                 pq.push(dijnode(_line[i].v,dis[_line[i].v]));
             }
         }
     }
     for(int i=;i<=n;i++)printf("%d\n",dis[i]);

 }
 int kcnt[N];
 int Astar()
 {
     if(dis[s]>=INF)return -;
     memset(kcnt,,sizeof(kcnt));
     priority_queue<Anode> pq;
     pq.push(Anode(s,,dis[s]));
     Anode node;
     while(!pq.empty())
     {
         node = pq.top();
         pq.pop();
         if(kcnt[node.v]>=k)continue;

         kcnt[node.v]++;
         if(kcnt[t]>=k)return node.g;
         for(int i=head[node.v];i!=-;i = line[i].next)
         {
             pq.push(Anode(line[i].v,node.g+line[i].val,dis[line[i].v]));
         }
     }
     return -;

 }
 int main(int argc, const char * argv[])
 {

     while(scanf("%d%d",&n,&m)!=EOF)
     {
         input();
         scanf("%d%d%d",&s,&t,&k);
         dijkstra();
         printf("%d\n",Astar());
     }
 }