#645. Almost Increasing Subsequence
Almost Increasing Subsequence
Description
我们定义“几乎递增”序列表示这个序列没有 个连续的元素 使得 。
现在有一个长度为 的序列,有 次询问,每次问一个区间 ,你回答 中最长的“几乎递增”子序列长度。
Input
一行两个正整数 表示长度和查询个数。
Output
行每行 个整数,表示最长的“几乎递增”子序列长度。
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
3
4
3
1
4
2
7
1
Note
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 $3$.
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 $4$.
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 $3$.