QOJ.ac

QOJ

Límite de tiempo: 7.0 s Límite de memoria: 512 MB Puntuación total: 100 Hackeable ✓

#7243. 深紫

Estadísticas

将众所周知的算法进行推广,使其变得不再那么平凡,这总是很酷的!

给定一个字符串 $S$。你的任务是处理 $q$ 个所谓的 $\pi$-查询。每个 $\pi$-查询由两个整数参数 $l$ 和 $r$ ($1 \le l \le r \le |S|$) 确定。$\pi$-查询的答案是满足 $S[l \dots l + x - 1] = S[r - x + 1 \dots r]$ 的最大非负整数 $x \le r - l$(所有区间均为闭区间,索引从 1 开始)。注意,$x = 0$ 总是满足给定条件,因为等式两边都是空字符串。

例如,对于字符串 $S = \text{“gabacababad”}$,$l = 2$ 且 $r = 8$ 的 $\pi$-查询结果为 $3$,因为 $S[2 \dots 4] = S[6 \dots 8] = \text{“aba”}$,且没有更大的值满足上述条件。

输入格式

第一行包含两个整数 $n$ 和 $q$ ($1 \le n, q \le 2 \cdot 10^5$),分别表示字符串 $S$ 的长度和查询次数。

第二行包含由 $n$ 个小写英文字母组成的字符串 $S$。

接下来的 $q$ 行,每行包含两个正整数 $l_i, r_i$ ($1 \le l_i \le r_i \le n$),描述第 $i$ 个 $\pi$-查询。

输出格式

按输入顺序输出每个查询的答案。

样例

样例输入 1

11 3
gabacababad
2 8
1 3
6 10

样例输出 1

3
0
3

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.