Time Limit: 2 Seconds
Memory Limit: 65536 KB
An unbounded triangular grid is a plane covered by equilateral triangles:
Two neighboring triangles in the grid form a rhomb. There are 3 types of such
A grid polygon is a simple polygon which sides consist entirely of sides of
triangles in the grid. We say that a grid polygon is rhombastic if it can be
partitioned into internally disjoint rhombs of types A, B and C.
As an example let's consider the following grid hexagon:
This hexagon can be partitioned into 4 rhombs of type A, 4 rhombs of type
B and 4 rhombs of type C:
For a given rhombastic grid polygon P compute the numbers of rhombs of types
A, B and C in some correct partition.
Write a program that:
> reads a description of a rhombastic grid polygon from the standard input,
> computes the numbers of rhombs of types A, B and C in some correct partition
of the polygon,
> writes the results to the standard output.
The first line of the input contains an integer n (3 <= n <= 50 000) -
the number of sides of a rhombastic grid polygon. Each of the next n lines contains
a description of one side of the polygon. The sides are given one by one in
the clockwise order. No two consecutive sides of the polygon lie on the same
straight line. The description of a side consists of two integers d and k. Integer
d says what is the direction of the side according to the following figure:
Integer k is the length of the polygon side measured in the number of sides
of grid triangles. Sum of all numbers k is not larger than 100 000.
Process to the end of file.
The first and only line of the output contains three integers separated by single
spaces denoting the number of rhombs of type A, B and C respectively, in some
partition of the input polygon.
4 4 4
Source: Central Europe 2002