#5034. Sugoroku 5

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Sugoroku 5

Sugoroku 5

题目描述

There is a board game with N+1N+1 squares: square 00, square 11, …\dots, square NN.
You have a die (dice) that rolls an integer between 11 and KK, inclusive, with equal probability for each outcome.
You start on square 00. You repeat the following operation until you reach square NN:

Roll the dice. Let xx be the current square and yy be the rolled number, then move to square min⁡(N,x+y)\min(N, x + y).

Let PiP_i be the probability of reaching square NN after exactly ii operations. Calculate P1,P2,…,PNP_1, P_2, \dots, P_N modulo 998244353998244353.

What is probability modulo $998244353$? It can be proved that the sought probabilities will always be rational numbers. Under the constraints of this problem, it can also be proved that when expressing the values as $\frac{P}{Q}$ using two coprime integers $P$ and $Q$, there is exactly one integer $R$ satisfying $R \times Q \equiv P\pmod{998244353}$ and $0 \leq R < 998244353$. Find this $R$.

输入格式

The input is given from Standard Input in the following format: NN KK

输出格式

Print NN lines. The ii-th line should contain PiP_i modulo 998244353998244353.

3 2
0
249561089
748683265
5 5
598946612
479157290
463185380
682000542
771443236
10 6
0
166374059
207967574
610038216
177927813
630578223
902091444
412046453
481340945
404612686

提示

1≤K≤N≤2×1051 \leq K \leq N \leq 2 \times 10^5 NN and KK are integers.For example, you reach square NN after exactly two operations when the die rolls the following numbers:

A 11 on the first operation, and a 22 on the second operation. A 22 on the first operation, and a 11 on the second operation. A 22 on the first operation, and a 22 on the second operation.

Therefore, $P_2 = \left( \frac{1}{2} \times \frac{1}{2} \right) \times 3 = \frac{3}{4}$. We have 249561089×4≡3(mod998244353)249561089 \times 4 \equiv 3 \pmod{998244353}, so print 249561089249561089 for P2P_2.

标签: AtCoder|abc345G

来源

AtCoder|abc345G