LINES  Game of Lines
Farmer John has challenged Bessie to the following game: FJ has a board with dots marked at N (2 ≤ N ≤ 200) distinct lattice points. Dot i has the integer coordinates X_{i} and Y_{i} (1,000 ≤ X_{i}, Y_{i} ≤ 1,000).
Bessie can score a point in the game by picking two of the dots and drawing a straight line between them; however, she is not allowed to draw a line if she has already drawn another line parallel to it. Bessie would like to know her chances of winning, so she has asked you to help find the maximum score she can obtain.
Input
There will be multiple test cases. For each case, the first line contains the integer N, and each of the next N lines gives a pair of integers, X_{i} and Y_{i}. The file ends with the case N = 0, which should not be processed.
Output
For each test case, print a single integer representing the maximum number of lines Bessie can draw, no two of which are parallel.
Example
Input: 4 1 1 2 0 0 0 1 1 0 Output: 4
Bessie can draw lines of the following four slopes: 1, 0, ⅓, and 1.
hide comments
hafiz031:
20180421 23:09:03
I used set to store all unique tangent values and stored a large number greater than possible input values for infinite case...and it worked!!...don't worry about +ve or ve inf as they are parallel and we can take only one either one or both of them occur...finally I printed the size of the set. 

amulyagaur:
20170519 09:06:28
stl rockssss 

Ray Brish Bhanu:
20160818 15:34:59
take care of infinity slope and  infinity slope 

minhthai:
20160212 10:29:20
help! can someone give a tricky test case?


ASHUTOSH DWIVEDI:
20150821 21:40:01
easy with STL but can be done without STL.... 

shantanu tripathi:
20150810 14:01:16
yes @mayank pratap.... made easy through STL 

[Mayank Pratap]:
20150731 15:26:15
STL becoming easier day by day... :) 

Dhruv Mullick:
20150525 21:48:52
Slope = infinity and infinity give the same line 

krishna kumar:
20140703 10:41:56
sam algo gav WA in python ..... but right in C++ ...


krishna kumar:
20140703 10:41:56
sam algo gav WA in python ..... but right in C++ ...

Added by:  Neal Wu 
Date:  20081019 
Time limit:  1s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO 
Resource:  USACO Feb 2008 