102156: [AtCoder]ABC215 G - Colorful Candies 2
Description
Score : $600$ points
Problem Statement
There are $N$ candies arranged in a row from left to right.
Each candy has one of the following $10^9$ colors: Color $1$, Color $2$, $\ldots$, Color $10^9$.
For each $i = 1, 2, \ldots, N$, the $i$-th candy from the left has Color $c_i$.
Takahashi will choose $K$ from the $N$ candies and get those $K$ candies.
There are $\binom{N}{K}$ ways to choose $K$ from the $N$ candies, where $\binom{N}{K}$ is a binomial coefficient. Takahashi will randomly select one of these $\binom{N}{K}$ ways with equal probability.
Because Takahashi wants to eat colorful candies, the more variety of colors his candies have, the happier he will be.
For each scenario $K = 1, 2, \ldots, N$, find the expected value of the number of different colors Takahashi's candies will have.
We can prove that the sought value is a rational number. Print this rational number modulo $998244353$, as described in Notes.
Notes
When you print a rational number, first write it as a fraction $\frac{y}{x}$, where $x, y$ are integers and $x$ is not divisible by $998244353$ (under the constraints of the problem, such representation is always possible). Then, you need to print the only integer $z$ between $0$ and $P - 1$, inclusive, that satisfies $xz \equiv y \pmod{998244353}$.
Constraints
- $1 \leq N \leq 5 \times 10^4$
- $1 \leq c_i \leq 10^9$
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
$N$ $c_1$ $c_2$ $\ldots$ $c_N$
Output
Print $N$ lines. The $i$-th line should contain the expected value of the number of different colors Takahashi's candies will have for the scenario $K = i$, modulo $998244353$ as described in Notes.
Sample Input 1
3 1 2 2
Sample Output 1
1 665496237 2
When $K = 1$, he will get the $1$-st candy, $2$-nd candy, or $3$-rd candy. In any case, his candy will have one color, so the expected value of the number of different colors is $1$.
When $K = 2$, he will get the $1$-st and $2$-nd candies, $2$-nd and $3$-rd candies, or $1$-st and $3$-rd candies.
- If he gets the $1$-st and $2$-nd candies, they have two different colors.
- If he gets the $2$-nd and $3$-rd candies, they have one color.
- If he gets the $1$-st and $3$-rd candies, they have two different colors.
Thus, the expected value of the number of different colors is $\frac{1}{3} \cdot 2 + \frac{1}{3} \cdot 1 + \frac{1}{3} \cdot 2 = \frac{5}{3}$.
Be sure to print it modulo $998244353$ as described in Notes.
When $K = 3$, he will always get the $1$-st, $2$-nd, and $3$-rd candies, which have two different colors, so the expected value of the number of different colors is $2$.
Sample Input 2
11 3 1 4 1 5 9 2 6 5 3 5
Sample Output 2
1 725995895 532396991 768345657 786495555 937744700 574746754 48399732 707846002 907494873 7
Input
题意翻译
现在有 $n$ 个糖果, 每个糖果有一种颜色 $c_i$. 现在高桥君想要在中间选 $k$ 个糖果. 由于他想吃最多种颜色的糖果, 所以他的快乐值是选择的糖果的颜色种类数. 例如, 选择糖果的颜色是 $\{2,3,3\}$, 那么他的快乐值是 $2$. 对于 $\forall k \in [1,n]$, 求出高桥君随机选择 $k$ 个糖果的快乐值的期望值, 对 $998244353$ 取模. $n \le 5 \times 10^4$, $c_i \le 10^9$.Output
分数:600分
问题描述
从左到右有$N$颗糖果。
每颗糖果有以下$10^9$种颜色之一:颜色$1$,颜色$2$,$\ldots$,颜色$10^9$。
对于每个$i = 1, 2, \ldots, N$,从左边数的第$i$颗糖果有颜色$c_i$。
高桥将从这$N$颗糖果中选择$K$颗,并获得这些$K$颗糖果。
从$N$颗糖果中选择$K$颗的方法有$\binom{N}{K}$种,其中$\binom{N}{K}$是一个二项式系数。高桥将以相等的概率随机选择这些方法之一。
因为高桥喜欢吃多彩的糖果,所以他糖果的颜色种类越多,他就会越开心。
对于每个场景$K = 1, 2, \ldots, N$,找出高桥糖果将具有的不同颜色数量的期望值。
我们可以证明所求值是一个有理数。根据Notes中的描述,将这个有理数对$998244353$取模打印。
注意
当你打印一个有理数时,首先要将其写为$\frac{y}{x}$的形式,其中$x, y$是整数且$x$不被$998244353$整除(在问题的约束下,这种表示总是可能的)。
然后,你需要打印一个在$0$到$P - 1$之间的整数$z$,满足$xz \equiv y \pmod{998244353}$。
约束
- $1 \leq N \leq 5 \times 10^4$
- $1 \leq c_i \leq 10^9$
- 输入中的所有值都是整数。
输入
输入通过标准输入给出以下格式:
$N$ $c_1$ $c_2$ $\ldots$ $c_N$
输出
打印$N$行。第$i$行应包含对于场景$K = i$,高桥糖果将具有的不同颜色数量的期望值,按照Notes中的描述对$998244353$取模打印。
样例输入1
3 1 2 2
样例输出1
1 665496237 2
当$K = 1$时,他将获得第$1$颗糖果,第$2$颗糖果,或第$3$颗糖果。无论怎样,他的糖果将有一种颜色,所以不同颜色数量的期望值为$1$。
当$K = 2$时,他将获得第$1$颗和第$2$颗糖果,第$2$颗和第$3$颗糖果,或第$1$颗和第$3$颗糖果。
- 如果他获得第$1$颗和第$2$颗糖果,它们有两种不同的颜色。
- 如果他获得第$2$颗和第$3$颗糖果,它们有一种颜色。
- 如果他获得第$1$颗和第$3$颗糖果,它们有两种不同的颜色。
因此,不同颜色数量的期望值为$\frac{1}{3} \cdot 2 + \frac{1}{3} \cdot 1 + \frac{1}{3} \cdot 2 = \frac{5}{3}$。
请确保按照Notes中的描述对$998244353$取模打印。
当$K = 3$时,他将总是获得第$1$,$2$,和$3$颗糖果,它们有两种不同的颜色,所以不同颜色数量的期望值为$2$。
样例输入2
11 3 1 4 1 5 9 2 6 5 3 5
样例输出2
1 725995895 532396991 768345657 786495555 937744700 574746754 48399732 707846002 907494873 7