Tokitsukaze and Beautiful Subsegments
题意翻译
给定一个长度为 $n$ 的**排列** $p$。
定义一个区间 $[l,r]$ 是美丽的当且仅当该区间中存在两个 $i,j$ 满足 $l\leq i<j\leq r$,且有 $a_ia_j=\max\limits_{k=l}^ra_k$。
现有 $q$ 组询问,每组询问给定区间 $[l_i,r_i]$,请你求出其有多少个子区间是美丽的。
$1\leq n\leq2\times10^5$,$1\leq q\leq 10^6$。
题目描述
Tokitsukaze has a permutation $ p $ of length $ n $ .
Let's call a segment $ [l,r] $ beautiful if there exist $ i $ and $ j $ satisfying $ p_i \cdot p_j = \max\{p_l, p_{l+1}, \ldots, p_r \} $ , where $ l \leq i < j \leq r $ .
Now Tokitsukaze has $ q $ queries, in the $ i $ -th query she wants to know how many beautiful subsegments $ [x,y] $ there are in the segment $ [l_i,r_i] $ (i. e. $ l_i \leq x \leq y \leq r_i $ ).
输入输出格式
输入格式
The first line contains two integers $ n $ and $ q $ ( $ 1\leq n \leq 2 \cdot 10^5 $ ; $ 1 \leq q \leq 10^6 $ ) — the length of permutation $ p $ and the number of queries.
The second line contains $ n $ distinct integers $ p_1, p_2, \ldots, p_n $ ( $ 1 \leq p_i \leq n $ ) — the permutation $ p $ .
Each of the next $ q $ lines contains two integers $ l_i $ and $ r_i $ ( $ 1 \leq l_i \leq r_i \leq n $ ) — the segment $ [l_i,r_i] $ of this query.
输出格式
For each query, print one integer — the numbers of beautiful subsegments in the segment $ [l_i,r_i] $ .
输入输出样例
输入样例 #1
8 3
1 3 5 2 4 7 6 8
1 3
1 1
1 8
输出样例 #1
2
0
10
输入样例 #2
10 10
6 1 3 2 5 8 4 10 7 9
1 8
1 10
1 2
1 4
2 4
5 8
4 10
4 7
8 10
5 9
输出样例 #2
17
25
1
5
2
0
4
1
0
0
说明
In the first example, for the first query, there are $ 2 $ beautiful subsegments — $ [1,2] $ and $ [1,3] $ .