Triple Index

AtCoder

IDabc293_g

Time3000ms

Memory256MB

Difficulty—

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 * $A_i = A_j = A_k$. ## 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. ## Input The input is given from Standard Input in the following format: $N$ $Q$ $A_1$ $A_2$ $\ldots$ $A_N$ $l_1$ $r_1$ $l_2$ $r_2$ $\vdots$ $l_Q$ $r_Q$ [samples]

Samples

Input #1

10 4
2 7 1 8 2 8 1 8 2 8
1 10
1 9
2 10
5 5

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 $(6, 8, 10)$.

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

Output #2

API Response (JSON)

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    "name": "Triple Index",
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      "content": "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 $(l_",
      "description_type": "Markdown"
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      "memory_limit": 262144
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    "difficulty": "None",
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    "sign": "abc293_g"
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    {
      "statement_type": "Markdown",
      "content": "You are given a length-$N$ sequence $(A_1, A_2, \\ldots, A_N)$ of positive integers, and $Q$ queries about the sequence.\nFor each $q = 1, 2, \\ldots, Q$, the $q$\\-th query gives you an integer pair $(l_...",
      "is_translate": false,
      "language": "English"
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