HDU 3371 connect the cities

And check the set + set container Kruskal

 # Include  <  Stdio. h  >  
# Include  <  String  . H  >  
# Include  <  Set  >  
  Using    Namespace  STD;
  Const     Int  Maxn  =     501  ;
  Struct  E
{
  Int  X, Y;
  Int  Weight;
};
E edge [  25001 ];
  Int  Father [maxn];

  Int  CMP (  Const     Void     *  D1,  Const     Void     *  D2 ){
 Return  (  *  (E  *  ) D1). Weight  -  (  *  (E  *  ) D2). weight;
}

  Void  Makeset (  Int  N ){
  For (  Int  I  =     0  ; I  <=  N; I  ++  )
Father [I]  =  I;
}

  Int  Find (  Int  X ){
 If  (X  ! =  Father [x])
Father [x]  =  Find (father [x]);
  Return  Father [x];
}

  Void  Merge (  Int  X,  Int  Y ){
  If  (X  > Y ){
Father [x]  =  Y;
}  Else  {
Father [y]  =  X;
}
}

  Int  Main (){
  Set  <  Int  >  S;
  Int  CAS, n, m, K, cost;
Scanf ( "  % D  "  ,  &  CAS );
  While  (CAS  --  ){
Scanf (  "  % D  "  ,  &  N,  &  M, &  K );
S. Clear ();
Makeset (N );
Cost  =     0  ;
  For  (  Int  I  =     1  ; I  <=  M; I  ++ ){
Scanf (  "  % D  "  ,  &  Edge [I]. X,  &  Edge [I]. y,  &  Edge [I]. weight );
}
  Int  Num, first, city;
  For  (  Int I  =     1  ; I  <=  K; I  ++  ){
Scanf (  "  % D  "  ,  &  Num,  &  First );
 For  (  Int  J  =     1  ; J  <  Num; j  ++  ){
Scanf (  "  % D  "  ,  &  City );
 Int  Xx  =  Find (first );
  Int  YY  =  Find (city );
  If  (Xx  ! =  YY)
Merge (XX, YY );
}
}
Qsort (edge  +  1  , M,  Sizeof (E), CMP );
  For  (  Int  I  =     1  ; I  <=  M; I  ++  ){
  Int  Xx  =  Find (edge [I]. X );
 Int  YY  =  Find (edge [I]. y );
  If  (Xx  ! =  YY ){
Merge (XX, YY );
Cost  + =  Edge [I]. weight;
}
}
  For  (  Int  I  =    1  ; I  <=  N; I  ++  ){
Find (I );
}
  For  (  Int  I  =     1  ; I  <=  N; I  ++ ){
S. insert (father [I]);
}
  If  (S. Size ()  >     1  ){
Printf (  "  -1 \ n  "  );
}  Else  {
Printf (  "  % D \ n  " , Cost );
}
}
  Return     0  ;
}