AtCoder Beginner Contest 133
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Problem Statement
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There are $N$ points in a $D$-dimensional space.
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The coordinates of the $i$-th point are $(X_{i1}, X_{i2}, ..., X_{iD})$.
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The distance between two points with coordinates $(y_1, y_2, ..., y_D)$ and $(z_1, z_2, ..., z_D)$ is $\sqrt{(y_1 - z_1)^2 + (y_2 - z_2)^2 + ... + (y_D - z_D)^2}$.
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How many pairs $(i, j)$ $(i < j)$ are there such that the distance between the $i$-th point and the $j$-th point is an integer?
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Constraints
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- All values in input are integers.
$2 \leq N \leq 10$$1 \leq D \leq 10$$-20 \leq X_{ij} \leq 20$- No two given points have the same coordinates. That is, if
$i \neq j$, there exists$k$such that$X_{ik} \neq X_{jk}$.
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Input
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Input is given from Standard Input in the following format:
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N D
X_{11} X_{12} ... X_{1D}
X_{21} X_{22} ... X_{2D}
\vdots
X_{N1} X_{N2} ... X_{ND}
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Output
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Print the number of pairs $(i, j)$ $(i < j)$ such that the distance between the $i$-th point and the $j$-th point is an integer.
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样例
Input #1
3 2
1 2
5 5
-2 8
Output #1
1
The number of pairs with an integer distance is one, as follows:
- The distance between the first point and the second point is $\sqrt{|1-5|^2 + |2-5|^2} = 5$, which is an integer.
- The distance between the second point and the third point is $\sqrt{|5-(-2)|^2 + |5-8|^2} = \sqrt{58}$, which is not an integer.
- The distance between the third point and the first point is $\sqrt{|-2-1|^2+|8-2|^2} = 3\sqrt{5}$, which is not an integer.
Input #2
3 4
-3 7 8 2
-12 1 10 2
-2 8 9 3
Output #2
2
Input #3
5 1
1
2
3
4
5
Output #3
10
题目信息
题面与样例版权归 AtCoder 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。