#AT2138. F - Cards
F - Cards
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F - Cards
Score : $500$ points
Problem Statement
There are $N$ cards numbered $1,\ldots,N$. Card $i$ has $P_i$ written on the front and $Q_i$ written on the back.
Here, $P=(P_1,\ldots,P_N)$ and $Q=(Q_1,\ldots,Q_N)$ are permutations of $(1, 2, \dots, N)$.
How many ways are there to choose some of the $N$ cards such that the following condition is satisfied? Find the count modulo $998244353$.
Condition: every number $1,2,\ldots,N$ is written on at least one of the chosen cards.
Constraints
- $1 \leq N \leq 2\times 10^5$
- $1 \leq P_i,Q_i \leq N$
- $P$ and $Q$ are permutations of $(1, 2, \dots, N)$.
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
Output
Print the answer.
3
1 2 3
2 1 3
3
For example, if you choose Cards $1$ and $3$, then $1$ is written on the front of Card $1$, $2$ on the back of Card $1$, and $3$ on the front of Card $3$, so this combination satisfies the condition.
There are $3$ ways to choose cards satisfying the condition: $\{1,3\},\{2,3\},\{1,2,3\}$.
5
2 3 5 4 1
4 2 1 3 5
12
8
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
1