Colorful Candies 2

AtCoder
IDabc215_g
Time4000ms
Memory256MB
Difficulty
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. ## 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: $N$ $c_1$ $c_2$ $\ldots$ $c_N$ [samples] ## 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 $xz \equiv y \pmod{998244353}$.
Samples
Input #1
3
1 2 2
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 $2$.
Input #2
11
3 1 4 1 5 9 2 6 5 3 5
Output #2
1
725995895
532396991
768345657
786495555
937744700
574746754
48399732
707846002
907494873
7
API Response (JSON)
{
  "problem": {
    "name": "Colorful Candies 2",
    "description": {
      "content": "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 $i$",
      "description_type": "Markdown"
    },
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    "limit": {
      "time_limit": 4000,
      "memory_limit": 262144
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    "difficulty": "None",
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  "statements": [
    {
      "statement_type": "Markdown",
      "content": "There are $N$ candies arranged in a row from left to right.  \nEach candy has one of the following $10^9$ colors: Color $1$, Color $2$, $\\ldots$, Color $10^9$.  \nFor each $i = 1, 2, \\ldots, N$, the $i$...",
      "is_translate": false,
      "language": "English"
    }
  ]
}
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