Codeforces Round 450 (Div. 2)
A
Find Extra One
Codeforces
800
原题
←B →
翻译中…

You have $*n*$ distinct points on a plane, none of them lie on $*OY*$ axis. Check that there is a point after removal of which the remaining points are located on one side of the $*OY*$ axis.

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Input

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The first line contains a single positive integer $*n*$ ($2 ≤ *n* ≤ 10^{5}$).

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The following $*n*$ lines contain coordinates of the points. The $*i*$-th of these lines contains two single integers $*x*_{*i*}$ and $*y*_{*i*}$ ($|*x*_{*i*}|, |*y*_{*i*}| ≤ 10^{9}$, $*x*_{*i*} ≠ 0$). No two points coincide.

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Output

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Print "Yes" if there is such a point, "No" — otherwise.

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You can print every letter in any case (upper or lower).

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Note

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In the first example the second point can be removed.

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In the second example there is no suitable for the condition point.

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In the third example any point can be removed.

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样例

Input #1
3
1 1
-1 -1
2 -1
Output #1
Yes
InputCopy OutputCopy
Input #2
4
1 1
2 2
-1 1
-2 2
Output #2
No
InputCopy OutputCopy
Input #3
3
1 2
2 1
4 60
Output #3
Yes
InputCopy OutputCopy
题目信息
题号
900A
时间限制
1 s
内存限制
256 MB
标签
计算几何
模拟

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