Codeforces Round 658 (Div. 1)
E
Origami
Codeforces
3300
原题
← D→
翻译中…

After being discouraged by 13 time-limit-exceeded verdicts on an ugly geometry problem, you decided to take a relaxing break for arts and crafts.

翻译中…

There is a piece of paper in the shape of a simple polygon with $n$ vertices. The polygon may be non-convex, but we all know that proper origami paper has the property that any horizontal line intersects the boundary of the polygon in at most two points.

翻译中…

If you fold the paper along the vertical line $x=f$, what will be the area of the resulting shape? When you fold, the part of the paper to the left of the line is symmetrically reflected on the right side.

翻译中…

image

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Your task is to answer $q$ independent queries for values $f_1,\ldots,f_q$.

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Input

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The first line contains two integers $n$, $q$ ($3\le n\le 10^5, 1\le q\le 10^5$)  — the number of polygon vertices and queries, respectively.

翻译中…

Each of the next $n$ lines contains two integers $x_i$, $y_i$ ($|x_i|, |y_i|\le 10^5$)  — the coordinates of the $i$-th point of the polygon. The polygon has an edge connecting each pair of adjacent points in the input, and also an edge between $(x_1,y_1)$ and $(x_n,y_n)$. It is guaranteed that the polygon is non-degenerate and that any horizontal line intersects the boundary of the polygon in at most two points. In particular, no boundary edge is strictly horizontal. Two adjacent sides may be collinear.

翻译中…

Each of the next $q$ lines contains a single integer $f_i$ ($\min\limits_{j=1}^n(x_j) \lt f_i \lt \max\limits_{j=1}^n(x_j)$)  — the $x$-coordinate of the $i$-th fold query. It is guaranteed that all $f_i$ are distinct.

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Output

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For each query, output the area $A_i$ of the paper if you fold it along the line $x=f_i$.

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Your answer is considered correct if its absolute or relative error does not exceed $10^{-4}$.

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Formally, let your answer be $a$, and the jury's answer be $b$. Your answer is accepted if and only if $\frac{|a - b|}{\max{(1, |b|)}} \le 10^{-4}$.

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Note

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The first test, with the fold $f=-5$:

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image

翻译中…

The second test, with the fold $f=1$:

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image

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The third test, with the fold $f=-1$:

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image

翻译中…

样例

Input #1
4 7
0 10
10 0
0 -10
-10 0
-9
-5
-1
0
1
5
9
Output #1
199.0000000000
175.0000000000
119.0000000000
100.0000000000
119.0000000000
175.0000000000
199.0000000000
InputCopy OutputCopy
Input #2
4 1
0 0
0 2
2 4
2 2
1
Output #2
3.0000000000
InputCopy OutputCopy
Input #3
9 4
0 -3
2 -2
-1 -1
0 4
2 5
1 6
-2 3
-1 1
-3 0
0
-2
-1
1
Output #3
11.1250000000
11.7500000000
10.3446969697
11.3333333333
InputCopy OutputCopy
题目信息
题号
1381E
时间限制
4 s
内存限制
256 MB
标签
计算几何
数学
排序

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。