poj 2485 Highways

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<cmath>
#include<queue>
#include<map>
#include<cstring>
#include<vector>
using namespace std;
class Kru
{
public:
int x,y,dis;
}kru[250024];
int set[524];
bool cmp(Kru a , Kru b )
{
return a.dis < b.dis;
}
int find( int x )
{
return set[x] == x ? x : set[x] = find( set[x] );
}
int Kruscal( int N )
{
int ans,X,Y;
for( int i = 0 ; i < N ; i++ )
{
if( ( X = find( kru[i].x ) )!=( Y = find(kru[i].y) ) )
{
ans = kru[i].dis;
set[Y] =X;
}
}
return ans;
}
int main(  )
{
int N,Case,dis;
while( scanf( "%d",&Case )==1 )
{
while( Case -- )
{
int count = 0 ;
scanf( "%d",&N );
for( int i = 1 ; i <= N ; i++ )
{
set[i] = i;
for( int j = 1 ; j <= N; j ++ )
{
scanf( "%d",&dis );
kru[count].x = i;kru[count].y=j;
kru[count++].dis = dis;
}
}
sort( kru ,kru + count , cmp );
printf( "%d\n",Kruscal( count ) );
}
}
//system( "pause" );
return 0;
}