C :

#include<stdio.h>
int main()
{
	int a[105][105],v[105]={0},dis[105]={0};
	int i,j,t,n,min,node,sum=0;
	scanf("%d",&n);
	for (i=0;i<n;i++)
		for (j=0;j<n;j++)
			scanf("%d",&a[i][j]);
	v[0]=1;
	for (i=0;i<n;i++)
		dis[i]=a[0][i];
	for (i=1;i<n;i++)
	{
		node=-2;
		min=100000;
		for (j=1;j<n;j++)
		{
			if (v[j]==0 && dis[j]<min)
			{
				min=dis[j];
				node=j;
			}
		}
		v[node]=1;
		sum+=min;
		for (j=1;j<n;j++)
		{
			if (v[j]==0 && dis[j]>a[node][j])
				dis[j]=a[node][j];
		}
	}
	printf("%d\n",sum);
	return 0;
}

C++ :

#include<stdio.h>
int cost[560][560];
int use[56];
int dd[560][560];
int mincost[560];
int min(int a,int b)
{
    return a>b?b:a;
}
int main()
{
	
	int n;
	int v,i,j;
	scanf("%d",&n);
	for(i=0;i<n;i++)
	{
		for(j=0;j<n;j++)
		{
			scanf("%d",&v);
			if(dd[i][j]==0)
			{
		    		cost[i][j]=v;
	               cost[j][i]=v;
				   dd[i][j]=1;
				   dd[j][i]=1;
			}
			else
			{
				if(cost[i][j]>v)
				{
					cost[i][j]=v;
					cost[j][i]=v;
				}
			}
		}
		
	}
	
	
	
	for(i=0;i<n;i++)
	{
		use[i]=0;
		mincost[i]=10000000;
	}
	mincost[0]=0;
	int res=0;
	while(1)
	{
		int p=-1;
		for(i=0;i<n;i++)
		{
			//printf("\n");
			if(use[i]==0&&(p==-1||mincost[i]<mincost[p]))
			{// printf("%d  %d  %d %d\n",mincost[i],mincost[p],i,p);
				p=i;
				//printf("%d  %d  %d %d\n",mincost[i],mincost[p],i,p);
			}
		}
		if(p==-1)
		{
			break;
		}
		use[p]=1;
		res+=mincost[p];
		for(i=0;i<n;i++)
		{
			mincost[i]=min(mincost[i],cost[p][i]);
		}
        //  for(i=0;i<n;i++)
        //  {
        //      printf("%d ",mincost[i]);
        //  }
        //  printf("\n");
		
	}
	printf("%d\n",res);
 

return 1;
}

Pascal :

//codeless;

type
  hugeint=record
   fromv,endv,weight:longint;
end;
var elist:array[1..10001] of hugeint;
    g:array[1..500,1..500] of longint;
    cost:array[1..101,1..101] of longint;
     n,i,j,ans:longint;
procedure prim;
var w,min,m,s,i,j,k:longint;
 t:hugeint;
begin
 for i:=1 to n-1 do
  begin
   elist[i].fromv:=1;
   elist[i].endv:=i+1;
   elist[i].weight:=g[1,i+1];
  end;
 for k:=1 to n-1 do
  begin
   min:=maxlongint;
   m:=k;
   for j:=k to n-1 do
    if elist[j].weight<min then begin
     min:=elist[j].weight;
     m:=j;
     end;
     inc(ans,min);
  if m<>k then begin
   t:=elist[k];
   elist[k]:=elist[m];
   elist[m]:=t;
   end;
  j:=elist[k].endv;
  for i:=k+1 to n-1 do
   begin
    s:=elist[i].endv;
    w:=g[j,s];
    if (w<elist[i].weight) and (w<>maxlongint) then
     begin
      elist[i].weight:=w;
      elist[i].fromv:=j;
     end;
   end;
  end;
end;

begin
//assign(input,'agrinet.in');
//assign(output,'agrinet.out');
//reset(input);
//rewrite(output);
readln(n);

for i:=1 to n do
 for j:=1 to n do
  begin
   read(cost[i,j]);
  if cost[i,j]>0 then
   g[i,j]:=cost[i,j]
   else g[i,j]:=maxlongint;
  end;
prim;
writeln(ans);


// close(input);
// close(output);
end.