C++ :

#include <bits/stdc++.h>
using namespace std;

struct node{
	int x,y,len;	
}; 


int f[110];
node a[10010];
int t,k = 0;
int n,q;

int find(int x){
	return x == f[x]?x:f[x] = find(f[x]);
}

void merge(int x,int y){
	int fx = find(x);
	int fy = find(y);
	if(fx != fy){
		f[fx] = fy;
	}
}

bool cmp(node n1,node n2){
	return n1.len < n2.len;
}

int main() {
	cin>>n;
	for(int i = 1;i <= n;i++){
		for(int j = 1;j <= n;j++){
			cin>>t;
			if(i > j){
				k++;
				a[k].x = i;
				a[k].y = j;
				a[k].len = t;		
			}		
		}
	}
	
	for(int i = 1;i <= n;i++){
		f[i] = i;
	} 
	
	sort(a+1,a+k+1,cmp);
	cin>>q;
	int x,y;
	int c = 0;
	for(int i = 1;i <= q;i++){
		cin>>x>>y;
		if(find(x) != find(y)){
			c++;
			merge(x,y);
		}
	}
	
	if(c >= n - 1){
		cout<<0;
		return 0;
	}
	
	int s = 0;
	for(int i = 1;i <= k;i++){
		if(find(a[i].x) != find(a[i].y)){
			merge(a[i].x,a[i].y);
			c++;
			s = s + a[i].len;
		}
		
		if(c == n - 1){
			cout<<s;
			break;
		}
	}
}

Pascal :

var ans,n,min,i,j,q,p,x,y:longint;
a:array[0..101,0..101] of longint;
d,f:array[0..101] of longint;
v:array[0..101] of boolean;

procedure prim;
var i,j:longint;
begin
  for i:=1 to n do d[i]:=maxlongint;
  d[1]:=0;
  for i:=1 to n do f[i]:=1;
  for i:=1 to n do
  begin
    min:=maxlongint;
    for j:=1 to n do
      if (v[j]=false) and (d[j]<min) then
        begin
          min:=d[j];
          q:=j;
        end;
    ans:=ans+a[q,f[q]];
    v[q]:=true;
    for j:=1 to n do
      if (q<>j) and (v[j]=false) and (a[q,j]>=0) and (a[q,j]<d[j]) then
        begin
          d[j]:=a[q,j];
          f[j]:=q;
        end;
  end;
end;

begin
readln(n);
for i:=1 to n do
for j:=1 to n do
read(a[i,j]);
readln(p);
for i:=1 to p do
begin
  read(x,y);
  a[x,y]:=0;
  a[y,x]:=0;
end;
prim;
write(ans);
end.
AC