QOJ.ac

QOJ

Time Limit: 2 s Memory Limit: 256 MB Total points: 100

#1465. 不是我们的问题

Statistics

有人(不是我!)称一个由非负整数组成的长度为 $n$ 的数组是“好的”,当且仅当对于所有 $1 \le i < n$,满足 $a_i \cdot a_{i+1} \cdot \min(a_i, a_{i+1}) \le C$。

另一个人(我们与他们无关!)给了你一个长度为 $n$ 的数组,其中包含一些空位。请计算有多少种填充空位的方法使得该数组是“好的”,或者确定是否存在无穷多种方法。如果方案数是有限的,请输出其对 $998\,244\,353$ 取模的结果。

输入格式

第一行包含两个整数 $n$ 和 $C$ ($1 \le n \le 10^6, 0 \le C \le 10^{18}$),分别表示数组的长度和乘积约束。

第二行包含数组 $a$。每个元素要么是 $-1$(表示需要填充),要么是 $0$ 到 $10^{18}$ 之间的整数(包含边界)。

输出格式

如果方案数有无穷多种,输出 $-1$,否则输出方案数对 $998\,244\,353$ 取模的结果。

样例

输入 1

4 100
-1 7 2 -1

输出 1

104

输入 2

4 100
10 -1 -1 1

输出 2

240

输入 3

1 0
-1

输出 3

-1

输入 4

2 10
10 10

输出 4

0

Discussions

About Discussions

The discussion section is only for posting: General Discussions (problem-solving strategies, alternative approaches), and Off-topic conversations.

This is NOT for reporting issues! If you want to report bugs or errors, please use the Issues section below.

Open Discussions 0
No discussions in this category.

Issues

About Issues

If you find any issues with the problem (statement, scoring, time/memory limits, test cases, etc.), you may submit an issue here. A problem moderator will review your issue.

Guidelines:

  1. This is not a place to publish discussions, editorials, or requests to debug your code. Issues are only visible to you and problem moderators.
  2. Do not submit duplicated issues.
  3. Issues must be filed in English or Chinese only.
Active Issues 0
No issues in this category.
Closed/Resolved Issues 0
No issues in this category.