Shortest network Agri-Net and network Agri-Net

Shortest network Agri-Net and network Agri-Net
Problem description: John, a farmer, was elected as the mayor of his town! One of his campaign promises to build the Internet in town and connect to all farms. Of course, he needs your help. John has arranged a high-speed network line for his farm. He wants to share the line with other farms. To minimize consumption, he wants to build the shortest optical fiber to connect all farms. You will get a list of connection fees between farms. You must find the solution that connects all farms and uses the shortest fiber optics. The distance between two farms is no more than 100000. [Input format

The first line:	Number of farms,N(3 <= N <= 100).
Row 2..EndTail	The subsequent rows containN * NMatrix,The distance between each farm. TheoryThey areNLine, each line fromNWhich are separated by spaces. In fact, theyRestricted in80Therefore, some rows are followed by other rows. Of course, diagonalThe line will be0Because there will be no line fromIFarm to itself.

Output Format: only one output, including the minimum length of the optical fiber connecting to each farm. [Input example] agrinet. in 4 0 4 9 21 4 0 8 17 9 8 0 16 21 16 16 0 [Output example] agrinet. out 28

 1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 using namespace std; 6 int num=1; 7 struct node 8 { 9     int u;10     int v;11     int w;12     int next;13 }edge[10001];14 int head[10001];15 int f[10001];16 int tot=0;17 int cmp(const node &a,const node &b)18 {19     if(a.w<b.w)return 1;20     else return 0;21 }22 int find(int x)23 {24     if(f[x]!=x)25     f[x]=find(f[x]);26     return f[x];27 }28 void unionn(int x,int y)29 {30     int fx=find(x);31     int fy=find(y);32     if(fx!=fy)33     f[fx]=fy;34 }35 int main()36 {37     int n;38     scanf("%d",&n);39     for(int i=0;i<=n;i++)head[i]=-1;40     for(int i=0;i<=n;i++)f[i]=i;41     for(int i=1;i<=n;i++)42     {43         for(int j=1;j<=n;j++)44         {45             int kk;46             scanf("%d",&kk);47             if(kk!=0)48             {49                 edge[num].w=kk;50                 edge[num].u=i;51                 edge[num].v=j;52                 edge[num].next=head[i];53                 num++;54             }55         }56     }57     int k=0;58     sort(edge+1,edge+num,cmp);59     for(int i=1;i<=num-1;i++)60     {61         if(find(edge[i].u)!=find(edge[i].v))62         {63             unionn(edge[i].u,edge[i].v);64             tot=tot+edge[i].w;65             k++;66         }67         if(k==n-1)break;68     }69     printf("%d",tot);70     return 0;71 }