AtCoder Grand Contest 047
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Problem Statement
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You are given $N$ real values $A_1, A_2, \ldots, A_N$. Compute the number of pairs of indices $(i, j)$ such that $i < j$ and the product $A_i \cdot A_j$ is integer.
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Constraints
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$2 \leq N \leq 200\,000$$0 < A_i < 10^4$$A_i$is given with at most 9 digits after the decimal.
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Input
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Input is given from Standard Input in the following format.
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N
A_1
A_2
\vdots
A_N
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Output
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Print the number of pairs with integer product $A_i \cdot A_j$ (and $i < j$).
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样例
Input #1
5
7.5
2.4
17.000000001
17
16.000000000
Output #1
3
There are 3 pairs with integer product:
- $7.5 \cdot 2.4 = 18$
- $7.5 \cdot 16 = 120$
- $17 \cdot 16 = 272$
Input #2
11
0.9
1
1
1.25
2.30000
5
70
0.000000001
9999.999999999
0.999999999
1.000000001
Output #2
8
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。