HDU 3371 connect the cities (Minimum Spanning Tree prim)

Question connection: http://acm.hdu.edu.cn/showproblem.php? PID = 1, 3371

 

It is not difficult to note that we should define the cost between cities as 0, and use the common prim algorithm. I didn't use the Kruskal's algorithm ), because the data for this question is relatively large, and a large amount of data needs to be processed to make it 0, for fear of timeout t ^ t .....

 

 

 1 #include<iostream> 2 #include<cstdio> 3 #include<algorithm> 4  5 using namespace std; 6  7 #define inf 999999 8  9 int map[505][505],node[505],n,vis[505];10 int dd[505],sum;11 12 int Prim()13 {14     int tm=1;15     node[tm]=0;16     //vis[tm]=1;17     for(int k=1;k<=n;k++)18     {19         int minn=inf;20         for(int i=1;i<=n;i++)21         if(!vis[i]&&minn>node[i])22         {23             tm=i;24             minn=node[i];25         }26         vis[tm]=1;27         if(minn==inf)28         return 0;29 30         sum+=minn;31 32         for(int i=1;i<=n;i++)33         {34             if(!vis[i]&&node[i]>map[tm][i])35             node[i]=map[tm][i];36         }37     }38     return 1;39 }40 41 int main()42 {43     int T;44     scanf("%d",&T);45     while(T--)46     {47         int m,k;48         scanf("%d%d%d",&n,&m,&k);49         for(int i=1;i<=n;i++)50         {51             node[i]=inf;vis[i]=0;52             for(int j=1;j<=n;j++)53             map[i][j]=inf;54         }55         while(m--)56         {57             int a,b,d;58             scanf("%d%d%d",&a,&b,&d);59             if(map[a][b]>d)60             map[a][b]=map[b][a]=d;61         }62         while(k--)63         {64             int t;65             scanf("%d",&t);66             for(int i=1;i<=t;i++)67             {68                 scanf("%d",&dd[i]);69             }70             for(int i=1;i<=t;i++)71             {72                 for(int j=i+1;j<=t;j++)73                 map[dd[i]][dd[j]]=map[dd[j]][dd[i]]=0;74             }75         }76         sum=0;77         int flag=Prim();78         if(flag==0)79         printf("-1\n");80         else81         printf("%d\n",sum);82     }83     return 0;84 }

 

HDU 3371 connect the cities (Minimum Spanning Tree prim)