각 팀 인원이 n명으로 제한된 동전 던지기 배정 과정에서, 주어진 사람 집합이 모두 같은 팀이 될 확률을 998244353으로 나눈 나머지로 구한다.
어려움9조합론수학확률누적 합아직 제출이 없습니다시간 제한10초메모리 제한512 MBAssuming people numbered from \(1\) to \(2n\) are assigned to two teams of size \(n\) using the following non-deterministic procedure, find the probability that all people from the set \(A^i = \{a^i_1, a^i_2, \dots , a^i_{k_i}\}\) end up on the same team, for each of the given sets \(A^1, A^2, \dots , A^m\), and display it modulo 998 244 353:
The first line contains two integers \(n\) and \(m\) (\(2 \le n \le 10^5; 1 \le m \le 10^5\)).
The \(i\)-th of the next \(m\) lines describes set \(A^i\) and contains an integer \(k_i\) (\(2 \le k_i \le n\)), followed by \(k_i\) integers \(a^i_1, a^i_2, \dots , a^i_{k_i}\) (\(1 \le a^i_1 < a^i_2 < \dots < a^i_{k_i} \le 2n\)).
The sum of \(k_i\) does not exceed \(2 \cdot 10^5\).
For each \(i\) from \(1\) to \(m\), display the probability that all people from the set \(A^i\) end up on the same team.
It can be shown that any sought probability can be represented as an irreducible fraction \(\frac{p}{q}\) such that \(q \not\equiv 0 \mod{998 244 353}\). Then, there exists a unique integer \(r\) such that \(r \cdot q \equiv p \mod {998 244 353}\) and \(0 \le r < 998 244 353\), so display this \(r\).
In the first test case, people 1 and 2 (and people 3 and 4) end up on the same team with probability \(\frac{1}{2}\). For any other pair the probability is \(\frac{1}{4}\).