QOJ.ac

QOJ

Time Limit: 2 s Memory Limit: 512 MB Total points: 100

#1835. 花哨的公式

Statistics

给定一个质数 $p$ 和一对整数 $(a, b)$,使得它们的和不能被 $p$ 整除。在一次操作中,你可以执行以下操作之一:

  • 将 $(a, b)$ 替换为 $(2a \pmod p, (b + p - a) \pmod p)$
  • 将 $(a, b)$ 替换为 $((a + p - b) \pmod p, 2b \pmod p)$

你需要回答 $q$ 个询问。对于第 $i$ 个询问,求出将数对 $(a_i, b_i)$ 变换为数对 $(c_i, d_i)$ 所需的最少操作次数,或者确定这是不可能的。

注意,数字的顺序很重要。例如,对于 $p = 3$,$(1, 2)$ 和 $(2, 1)$ 之间的距离是 $1$,而不是 $0$。

输入格式

第一行包含两个整数 $p$ 和 $q$ ($2 \le p \le 10^9 + 7$,$p$ 是质数,$1 \le q \le 10^5$):表示质数和询问次数。

接下来的 $q$ 行中,第 $i$ 行包含四个整数 $a_i, b_i, c_i, d_i$ ($0 \le a_i, b_i, c_i, d_i < p$,且 $a_i + b_i$ 不能被 $p$ 整除)。

输出格式

对于每个询问,如果无法将 $(a_i, b_i)$ 变换为 $(c_i, d_i)$,输出 $-1$。否则,输出实现该目标所需的最少操作次数。

样例

样例输入 1

5 10
2 1 3 0
2 1 4 4
1 3 4 0
0 2 0 4
3 3 1 2
0 1 0 1
0 3 0 3
0 1 0 1
1 2 4 4
1 0 1 1

样例输出 1

2
1
2
-1
-1
0
0
0
1
-1

Editorials

IDTypeStatusTitlePosted ByLast UpdatedActions
EditorialOpen Official EditorialQingyu- Download

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.