Return distance between the centers
static long dis ( long x1 , long y1 , long x2 , long y2 ) { return ( long ) Math . sqrt ( ( x1 - x2 ) * ( x1 - x2 ) + ( y1 - y2 ) * ( y1 - y2 ) ) ; } static boolean check ( node c1 , node c2 , int k ) { long min = 0 ; long max = 0 ;