Codeforces Round 869 (Div. 2)
C
Almost Increasing Subsequence
Codeforces
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原题
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A sequence is almost-increasing if it does not contain three consecutive elements $x, y, z$ such that $x\ge y\ge z$.

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You are given an array $a_1, a_2, \dots, a_n$ and $q$ queries.

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Each query consists of two integers $1\le l\le r\le n$. For each query, find the length of the longest almost-increasing subsequence of the subarray $a_l, a_{l+1}, \dots, a_r$.

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A subsequence is a sequence that can be derived from the given sequence by deleting zero or more elements without changing the order of the remaining elements.

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Input

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The first line of input contains two integers, $n$ and $q$ ($1 \leq n, q \leq 200\,000$)  — the length of the array $a$ and the number of queries.

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The second line contains $n$ integers $a_1, a_2, \dots, a_n$ ($1 \leq a_i \leq 10^9$)  — the values of the array $a$.

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Each of the next $q$ lines contains the description of a query. Each line contains two integers $l$ and $r$ ($1 \leq l \leq r \leq n$)  — the query is about the subarray $a_l, a_{l+1}, \dots, a_r$.

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Output

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For each of the $q$ queries, print a line containing the length of the longest almost-increasing subsequence of the subarray $a_l, a_{l+1}, \dots, a_r$.

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Note

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In the first query, the subarray is $a_1, a_2, a_3 = [1,2,4]$. The whole subarray is almost-increasing, so the answer is $3$.

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In the second query, the subarray is $a_1, a_2, a_3,a_4 = [1,2,4,3]$. The whole subarray is a almost-increasing, because there are no three consecutive elements such that $x \geq y \geq z$. So the answer is $4$.

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In the third query, the subarray is $a_2, a_3, a_4, a_5 = [2, 4, 3, 3]$. The whole subarray is not almost-increasing, because the last three elements satisfy $4 \geq 3 \geq 3$. An almost-increasing subsequence of length $3$ can be found (for example taking $a_2,a_3,a_5 = [2,4,3]$ ). So the answer is $3$.

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样例

Input #1
9 8
1 2 4 3 3 5 6 2 1
1 3
1 4
2 5
6 6
3 7
7 8
1 8
8 8
Output #1
3
4
3
1
4
2
7
1
InputCopy OutputCopy
题目信息
题号
1818C
时间限制
2 s
内存限制
256 MB

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