题目描述
Problem Statement
You are given $a length-N sequence (A_1, A_2, \ldots, A_N)$ of positive integers, and Q queries about the sequence.
For each $q = 1, 2, \ldots, Q$, the q-th query gives you an integer pair (l_q, r_q);
print the number of integer triplets (i, j, k) such that
- $l_q \leq i \lt j \lt k \leq r_q$, and
- A_i = A_j = A_k.
Input
The input is given from Standard Input in the following format:
N Q
$A_1 A_2 \ldots A_N$
l_1 r_1
l_2 r_2
$\vdots$
l_Q r_Q
Output
Print Q lines.
For $q = 1, 2, \ldots, Q$, the q-th line should contain the answer to the q-th query.
Constraints
- $1 \leq N \leq 2 \times 10^5$
- $1 \leq Q \leq 2 \times 10^5$
- $1 \leq A_i \leq 2 \times 10^5$
- $1 \leq l_q \leq r_q \leq N$
- All values in the input are integers.
Sample Input 1
10 4
2 7 1 8 2 8 1 8 2 8
1 10
1 9
2 10
5 5
Sample Output 1
5
2
4
0
For the first query, there are five triplets of integers that satisfy the conditions in the problem statement:
(1, 5, 9), (4, 6, 8), (4, 6, 10), (4, 8, 10), and (6, 8, 10).
Sample Input 2
20 10
2 2 2 2 1 1 2 2 1 1 1 2 1 2 1 2 2 1 2 1
12 16
17 18
12 18
4 9
13 13
2 5
6 13
2 14
7 14
8 12
Sample Output 2
1
0
5
2
0
1
11
55
8
1
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分