103145: [Atcoder]ABC314 F - A Certain Game
Description
Score : $475$ points
Problem Statement
$N$ players, player $1$, player $2$, ..., player $N$, participate in a game tournament. Just before the tournament starts, each player forms a one-person team, so there are $N$ teams in total.
The tournament has a total of $N-1$ matches. In each match, two different teams are chosen. One team goes first, and the other goes second. Each match will result in exactly one team winning. Specifically, for each $i = 1, 2, \ldots, N-1$, the $i$-th match proceeds as follows.
- The team with player $p_i$ goes first, and the team with player $q_i$ goes second.
- Let $a$ and $b$ be the numbers of players in the first and second teams, respectively. The first team wins with probability $\frac{a}{a+b}$, and the second team wins with probability $\frac{b}{a+b}$.
- Then, the two teams are combined into a single team.
The result of each match is independent of those of the others.
For each of the $N$ players, print the expected number of times the team with that player wins throughout the tournament, modulo $998244353$.
How to print an expected value modulo $998244353$
It can be proved that the sought expected value is always rational. Also, the constraints of this problem guarantee that if the sought expected value is expressed as an irreducible fraction $\frac{y}{x}$, then $x$ is not divisible by $998244353$.
Now, there is a unique integer $z$ between $0$ and $998244352$, inclusive, such that $xz \equiv y \pmod{998244353}$. Report this $z$.
Constraints
- $2 \leq N \leq 2 \times 10^5$
- $1 \leq p_i, q_i \leq N$
- Just before the $i$-th match, player $p_i$ and player $q_i$ belong to different teams.
- All input values are integers.
Input
The input is given from Standard Input in the following format:
$N$ $p_1$ $q_1$ $p_2$ $q_2$ $\vdots$ $p_{N-1}$ $q_{N-1}$
Output
For each $i = 1, 2, \ldots, N$, print $E_i$, the expected number, modulo $998244353$, of times the team with player $i$ wins throughout the tournament, separated by spaces, in the following format:
$E_1$ $E_2$ $\ldots$ $E_N$
Sample Input 1
5 1 2 4 3 5 3 1 4
Sample Output 1
698771048 698771048 964969543 964969543 133099248
We call a team formed by player $x_1$, player $x_2$, $\ldots$, player $x_k$ as team $\lbrace x_1, x_2, \ldots, x_k \rbrace$.
- The first match is played by team $\lbrace 1 \rbrace$, with player $1$, and team $\lbrace 2 \rbrace$, with player $2$. Team $\lbrace 1 \rbrace$ wins with probability $\frac{1}{2}$, and team $\lbrace 2 \rbrace$ wins with probability $\frac{1}{2}$. Then, the two teams are combined into a single team $\lbrace 1, 2 \rbrace$.
- The second match is played by team $\lbrace 4 \rbrace$, with player $4$, and team $\lbrace 3 \rbrace$, with player $3$. Team $\lbrace 4 \rbrace$ wins with probability $\frac{1}{2}$, and team $\lbrace 3 \rbrace$ wins with probability $\frac{1}{2}$. Then, the two teams are combined into a single team $\lbrace 3, 4 \rbrace$.
- The third match is played by team $\lbrace 5 \rbrace$, with player $5$, and team $\lbrace 3, 4 \rbrace$, with player $3$. Team $\lbrace 5 \rbrace$ wins with probability $\frac{1}{3}$, and team $\lbrace 3, 4 \rbrace$ wins with probability $\frac{2}{3}$. Then, the two teams are combined into a single team $\lbrace 3, 4, 5 \rbrace$.
- The fourth match is played by team $\lbrace 1, 2 \rbrace$, with player $1$, and team $\lbrace 3, 4, 5 \rbrace$, with player $4$. Team $\lbrace 1, 2 \rbrace$ wins with probability $\frac{2}{5}$, and team $\lbrace 3, 4, 5 \rbrace$ wins with probability $\frac{3}{5}$. Then, the two teams are combined into a single team $\lbrace 1, 2, 3, 4, 5 \rbrace$.
The expected numbers of times the teams with players $1, 2, 3, 4, 5$ win throughout the tournament, $E_1, E_2, E_3, E_4, E_5$, are $\frac{9}{10}, \frac{9}{10}, \frac{53}{30}, \frac{53}{30}, \frac{14}{15}$, respectively.
Sample Input 2
15 9 2 8 10 13 6 12 11 7 10 4 10 14 2 5 4 1 15 15 2 6 9 8 11 6 3 2 8
Sample Output 2
43970290 310168785 806914186 501498951 950708909 272140427 335124893 168750835 310168785 168750835 280459129 280459129 272140427 476542843 43970290
Output
问题描述
$N$个玩家,玩家$1$,玩家$2$,...,玩家$N$参加一个游戏比赛。在比赛开始前,每个玩家组成一个单人队伍,所以总共有$N$个队伍。
比赛总共有$N-1$场。每场比赛,选择两个不同的队伍。一个队伍先手,另一个队伍后手。每场比赛只会有一个队伍获胜。具体来说,对于每个$i = 1, 2, \ldots, N-1$,第$i$场比赛进行如下。
- 玩家$p_i$所在的队伍先手,玩家$q_i$所在的队伍后手。
- 设第一个队伍和第二个队伍的玩家数量分别为$a$和$b$。第一个队伍获胜的概率为$\frac{a}{a+b}$,第二个队伍获胜的概率为$\frac{b}{a+b}$。
- 然后,这两个队伍合并为一个队伍。
每场比赛的结果与其他比赛的结果无关。
对于每个玩家,输出在整个比赛期间,该玩家所在的队伍获胜的期望次数,对$998244353$取模。
如何对$998244353$取模输出期望值
可以证明,所求的期望值总是有理数。此外,本问题的约束条件保证了,如果所求的期望值表示为不可约分数$\frac{y}{x}$,那么$x$不被$998244353$整除。
现在,存在一个唯一的整数$z$,其范围在$0$到$998244352$之间(包括这两个数),满足$xz \equiv y \pmod{998244353}$。报告这个$z$。
约束条件
- $2 \leq N \leq 2 \times 10^5$
- $1 \leq p_i, q_i \leq N$
- 在第$i$场比赛开始前,玩家$p_i$和玩家$q_i$属于不同的队伍。
- 所有的输入值都是整数。
输入
输入从标准输入按以下格式给出:
$N$ $p_1$ $q_1$ $p_2$ $q_2$ $\vdots$ $p_{N-1}$ $q_{N-1}$
输出
对于每个$i = 1, 2, \ldots, N$,以空格分隔的方式输出$E_i$,即在整个比赛中,玩家$i$所在的队伍获胜的期望次数,对$998244353$取模,如下所示:
$E_1$ $E_2$ $\ldots$ $E_N$
样例输入 1
5 1 2 4 3 5 3 1 4
样例输出 1
698771048 698771048 964969543 964969543 133099248
我们称由玩家$x_1$,玩家$x_2$,$\ldots$,玩家$x_k$组成的队伍为队伍$\lbrace x_1, x_2, \ldots, x_k \rbrace$。
- 第一场比赛由队伍$\lbrace 1 \rbrace$,包含玩家$1$,和队伍$\lbrace 2 \rbrace$,包含玩家$2$进行。队伍$\lbrace 1 \rbrace$获胜的概率为$\frac{1}{2}$,队伍$\lbrace 2 \rbrace$获胜的概率为$\frac{1}{2}$。然后,这两个队伍合并为一个队伍$\lbrace 1, 2 \rbrace$。
- 第二场比赛由队伍$\lbrace 4 \rbrace$,包含玩家$4$,和队伍$\lbrace 3 \rbrace$,包含玩家$3$进行。队伍$\lbrace 4 \rbrace$获胜的概率为$\frac{1}{2}$,队伍$\lbrace 3 \rbrace$获胜的概率为$\frac{1}{2}$。然后,这两个队伍合并为一个队伍$\lbrace 3, 4 \rbrace$。
- 第三场比赛由队伍$\lbrace 5 \rbrace$,包含玩家$5$,和队伍$\lbrace 3, 4 \rbrace$,包含玩家$3$进行。队伍$\lbrace 5 \rbrace$获胜的概率为$\frac{1}{3}$,队伍$\lbrace 3, 4 \rbrace$获胜的概率为$\frac{2}{3}$。然后,这两个队伍合并为一个队伍$\lbrace 3, 4, 5 \rbrace$。
- 第四场比赛由队伍$\lbrace 1, 2 \rbrace$,包含玩家$1$,和队伍$\lbrace 3, 4, 5 \rbrace$,包含玩家$4$进行。队伍$\lbrace 1, 2 \rbrace$获胜的概率为$\frac{2}{5}$,队伍$\lbrace 3, 4, 5 \rbrace$获胜的概率为$\frac{3}{5}$。然后,这两个队伍合并为一个队伍$\lbrace 1, 2, 3, 4, 5 \rbrace$。
在整个比赛中,队伍$\lbrace 1, 2, 3, 4, 5 \rbrace$中玩家$1, 2, 3, 4, 5$获胜的期望次数分别为$\frac{9}{10}, \frac{9}{10}, \frac{53}{30}, \frac{53}{30}, \frac{14}{15}$。
样例输入 2
15 9 2 8 10 13 6 12 11 7 10 4 10 14 2 5 4 1 15 15 2 6 9 8 11 6 3 2 8
样例输出 2
43970290 310168785 806914186 501498951 950708909 272140427 335124893 168750835 310168785 168750835 280459129 280459129 272140427 476542843 43970290