CCO '12 P6 - The Winds Of War

View as PDF

Submit solution

Points: 12 (partial)
Time limit: 1.0s
Memory limit: 1G

Problem type
Canadian Computing Competition: 2012 Stage 2, Day 2, Problem 3

Colonel Trapp is trapped! For several days he has been fighting General Position on a plateau and his mobile command unit is now stuck at (0,0), on the edge of a cliff. But the winds are changing! The Colonel has a secret weapon up his sleeve: the "epsilon net". Your job, as the Colonel's chief optimization officer, is to determine the maximum advantage that a net can yield.

The epsilon net is a device that looks like a parachute, which you can launch to cover any convex shape. (A shape is convex when, for every pair p,q of points it contains, it also contains the entire line segment pq.) The net shape must include the launch point (0,0).

The General has P enemy units stationed at fixed positions and the Colonel has T friendly units. The advantage of a particular net shape equals the number of enemy units it covers, minus the number of friendly units it covers. The General is not a unit.

You can assume that

  • no three points (Trapp's position (0,0), enemy units, and friendly units) lie on a line,
  • every two points have distinct x-coordinates and y-coordinates,
  • all coordinates (x,y) of the units have y>0,
  • all coordinates are integers with absolute value at most 1000000000, and
  • the total number P+T of units is between 1 and 100.

Input Specification

The first line contains P and then T, separated by spaces. Subsequently, there are P lines of the form x y giving the enemy units' coordinates, and then T lines giving the friendly units' coordinates.

Output Specification

Output a single line with the maximum possible advantage.

Sample Input

Copy
5 3
-8 4
-7 11
4 10
10 5
8 2
-5 7
-4 3
5 6

Output for Sample Input

Copy
3
Figure 1: Sample input and an optimal net.

Comments

There are no comments at the moment.