#P8106. [Cnoi2021] 数学练习
[Cnoi2021] 数学练习
Description
To make contestants pay attention to regular school subjects, Cirno специально added a math exercise from teacher Kamishirasawa Keine:
Find the number of ways to partition a set into two subsets such that .
Since the contestants cannot do big-integer arithmetic, you only need to output the answer modulo .
Input Format
One line with one integer .
Output Format
One line with one integer, representing the answer.
3
2
6
10
65535
459810767
Hint
Sample Explanation.
#1: Two valid partition schemes are and .
Constraints.
For of the testdata, it is guaranteed that .
Reprinted from XDUCPC 2021 online contest problem B.
Translated by ChatGPT 5
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