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No.3045 反復重み付き累積和

レベル : / 実行時間制限 : 1ケース 5.000秒 / メモリ制限 : 512 MB / 標準ジャッジ問題
タグ : (AC するまで非表示) / 解いたユーザー数 39
作問者 : nauclhlt / テスター : eiram naniwazu
お気に入りにしたユーザー ProblemId : 11871 / 自分の提出
問題文最終更新日: 2025-02-28 21:27:41
Iterated Weighted Prefix Sum
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yukicoder contest 458 (順位表) の他の問題:

Story

nauclhlt is no longer satisfied with ordinary prefix sums. Nor can an ordinary number of prefix sum iterations satisfy him.
For example, how about taking the prefix sum $10^9$ times...

Problem Statement

We define the prefix sum with weight $K$ of a sequence $P$ as the sequence $Q$ of length $|P|$ satisfying the following.

  • $\displaystyle Q_i=\sum_{j=1}^i K^{i-j}P_j\ (1\leq i\leq |P|)$

Here, $|P|$ is the length of the sequence $P$.

You are given a sequence $A=(A_1, A_2, \cdots, A_N)$ of length $N$.
Process $Q$ queries of the following forms in order.

  • 1 k x: Repeat the operation "replace $A$ with the prefix sum with weight $k$ of $A$" $x$ times.
  • 2 x: Print the value of $A_x$ modulo $998244353$.

Input

$N\ Q$
$A_1\ A_2\ \cdots\ A_N$
$query_1$
$query_2$
$\vdots$
$query_Q$

Each query is given in one of the following formats.

$1\ k\ x$
$2\ x$
  • $1\leq N\leq 2000$
  • $0\leq A_i\lt 998244353$
  • $1\leq Q\leq 2000$
  • For queries of the form 1 k x, $1\leq k\lt 998244353, 1\leq x\leq 10^9$
  • For queries of the form 2 x, $1\leq x\leq N$
  • At least 1 query of the form 2 x is given.
  • All inputs are integers.

Output

Let $m$ be the number of queries of the form 2 x, and print $m$ lines.
On the $i(1\leq i\leq m)$-th line, print the answer to the $i$-th such query.
Print a newline at the end.

Sample

Sample 1
Input
4 3
3 1 4 1
2 3
1 2 1
2 3
Output
4
18
  • For the 1st query, $A_3=4$, so print 4.
  • For the 2nd query, the prefix sum with weight $2$ of $A$ is $(3, 7, 18, 37)$. Thus, replace $A$ with this sequence.
  • For the 3rd query, $A_3=18$, so print 18.
Sample 2
Input
3 2
1 1 2
1 3 2
2 2
Output
7

The prefix sum with weight $3$ of $A$ is $(1, 4, 14)$. Taking the prefix sum with weight $3$ of this sequence gives $(1, 7, 35)$. Thus, after the 1st query, $A=(1, 7, 35)$.
In the 2nd query, from the above result, $A_2=7$, so print 7.

Sample 3
Input
10 2
0 9 9 8 2 4 4 3 5 3
1 998244352 998244353
2 10
Output
3

Print the value modulo $998244353$.

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