Codeforces Round 291 (Div. 2)
B
Han Solo and Lazer Gun
Codeforces
1400
原题
← AC →
翻译中…

There are $*n*$ Imperial stormtroopers on the field. The battle field is a plane with Cartesian coordinate system. Each stormtrooper is associated with his coordinates $(*x*, *y*)$ on this plane.

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Han Solo has the newest duplex lazer gun to fight these stormtroopers. It is situated at the point $(*x*_{0}, *y*_{0})$. In one shot it can can destroy all the stormtroopers, situated on some line that crosses point $(*x*_{0}, *y*_{0})$.

翻译中…

Your task is to determine what minimum number of shots Han Solo needs to defeat all the stormtroopers.

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The gun is the newest invention, it shoots very quickly and even after a very large number of shots the stormtroopers don't have enough time to realize what's happening and change their location.

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Input

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The first line contains three integers $*n*$, $*x*_{0}$ и $*y*_{0}$ ($1 ≤ *n* ≤ 1000$, $- 10^{4} ≤ *x*_{0}, *y*_{0} ≤ 10^{4}$) — the number of stormtroopers on the battle field and the coordinates of your gun.

翻译中…

Next $*n*$ lines contain two integers each $*x*_{*i*}$, $*y*_{*i*}$ ($- 10^{4} ≤ *x*_{*i*}, *y*_{*i*} ≤ 10^{4}$) — the coordinates of the stormtroopers on the battlefield. It is guaranteed that no stormtrooper stands at the same point with the gun. Multiple stormtroopers can stand at the same point.

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Output

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Print a single integer — the minimum number of shots Han Solo needs to destroy all the stormtroopers.

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Note

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Explanation to the first and second samples from the statement, respectively:

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image

翻译中…

样例

Input #1
4 0 0
1 1
2 2
2 0
-1 -1
Output #1
2
InputCopy OutputCopy
Input #2
2 1 2
1 1
1 0
Output #2
1
InputCopy OutputCopy
题目信息
题号
514B
时间限制
1 s
内存限制
256 MB
标签
暴力
数据结构
计算几何
模拟
数学

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。