Author: | A. Klenin | Time limit: | 3 sec | |
Input file: | input.txt | Memory limit: | 64 Mb | |
Output file: | output.txt |
Classic geometric construction is based on two instruments: ruler and compass. However, some constructions are possible using only the ruler. Specifically, let us define that if we have a set of N points, we can select two pairs of them, draw a line through each pair, and construct a new point as an intersection of these two lines. New point can then be added to the set as (N + 1)-th point, and the process repeated.
Such geometric constructions are abstract notions, and attempt to verify them with physical pencil and ruler can lead to errors caused by imprecision of these instruments. So you are tasked to write a program that does exact verification.
Your program must read a set of points and a sequence of constructing operations and find out whether the point with coordinates (0, 0) is one of the constructed points. Note that, similar to physical instruments, floating point calculations performed by computers are also imprecise. This should not, of course, alter verification results.
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