Codeforces Round 654 (Div. 2)
F
Raging Thunder
Codeforces
2800
原题
← E2→
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You are a warrior fighting against the machine god Thor.

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Thor challenge you to solve the following problem:

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There are $n$ conveyors arranged in a line numbered with integers from $1$ to $n$ from left to right. Each conveyor has a symbol "<" or ">". The initial state of the conveyor $i$ is equal to the $i$-th character of the string $s$. There are $n+1$ holes numbered with integers from $0$ to $n$. The hole $0$ is on the left side of the conveyor $1$, and for all $i \geq 1$ the hole $i$ is on the right side of the conveyor $i$.

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When a ball is on the conveyor $i$, the ball moves by the next rules:

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If the symbol "<" is on the conveyor $i$, then:

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  • If $i=1$, the ball falls into the hole $0$.
  • If the symbol "<" is on the conveyor $i-1$, the ball moves to the conveyor $i-1$.
  • If the symbol ">" is on the conveyor $i-1$, the ball falls into the hole $i-1$.
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If the symbol ">" is on the conveyor $i$, then:

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  • If $i=n$, the ball falls into the hole $n$.
  • If the symbol ">" is on the conveyor $i+1$, the ball moves to the conveyor $i+1$.
  • If the symbol "<" is on the conveyor $i+1$, the ball falls into the hole $i$.
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You should answer next $q$ queries, each query is defined by the pair of integers $l, r$ ($1 \leq l \leq r \leq n$):

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  • First, for all conveyors $l,l+1,...,r$, the symbol "<" changes to ">" and vice versa. These changes remain for the next queries.
  • After that, put one ball on each conveyor $l,l+1,...,r$. Then, each ball falls into some hole. Find the maximum number of balls in one hole. After the query all balls disappear and don't considered in the next queries.
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Input

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The first line contains two integers $n$, $q$ ($1 \le n \le 5 \times 10^5 , 1 \le q \le 10^5$).

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The second line contains a string $s$ of length $n$. It consists of characters "<" and ">".

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Next $q$ lines contain the descriptions of the queries, $i$-th of them contains two integers $l$, $r$ $(1 \le l \le r \le n)$, describing the $i$-th query.

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Output

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Print $q$ lines, in the $i$-th of them print the answer to the $i$-th query.

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Note

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  • In the first query, the conveyors change to ">><<<". After that, put a ball on each conveyor $\{2,3,4\}$. All three balls fall into the hole $2$. So the answer is $3$.
  • In the second query, the conveyors change to ">>>>>". After that, put a ball on each conveyor $\{3,4,5\}$. All three balls fall into the hole $5$. So the answer is $3$.
  • In the third query, the conveyors change to "<<<<<". After that, put a ball on each conveyor $\{1,2,3,4,5\}$. All five balls fall into the hole $0$. So the answer is $5$.
  • In the fourth query, the conveyors change to ">>><<". After that, put a ball on each conveyor $\{1,2,3\}$. All three balls fall into the hole $3$. So the answer is $3$.
  • In the fifth query, the conveyors change to "><<><". After that, put a ball on each conveyor $\{2,3,4\}$. Two balls fall into the hole $1$, and one ball falls into the hole $4$. So, the answer is $2$.
  • In the sixth query, the conveyors change to "<>><>". After that, put a ball on each conveyor $\{1,2,3,4,5\}$. Three balls fall into the hole $3$, one ball falls into the hole $0$ and one ball falls into the hole $5$. So, the answer is $3$.
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样例

Input #1
5 6
><>><
2 4
3 5
1 5
1 3
2 4
1 5
Output #1
3
3
5
3
2
3
InputCopy OutputCopy
题目信息
题号
1371F
时间限制
3 s
内存限制
512 MB
标签
数据结构
分治
模拟

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。