This is my rather unconventional solution using sorted contest array(by start time or end time) and wormhole array. The solution yields O(NlogN) since it sorts the contest array twice by its start-time order and end-time order.

// ZCO15002
import java.util.*;
import java.lang.*;
 
// The following solution can be modified to use binarysearch on V and W without sorting P,
// which will yield faster runtime.
 
/* Name of the class has to be "Main" only if the class is public. */
class ZCO12002 {
  private static Scanner sc;
 
  public static class contest {
    int n1;
    int n2;
    int closest_v = -1;
    int closest_w = -1;
  }