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No.1270 Range Arrange Query

レベル : / AI推定難易度 : 2225 / 実行時間制限 : 1ケース 7.000秒 / メモリ制限 : 512 MB / 標準ジャッジ問題
タグ : (AC するまで非表示) / 解いたユーザー数 38
作問者 : stoq / テスター : tsutaj
お気に入りにしたユーザー ProblemId : 5223 / 自分の提出
問題文最終更新日: 2020-10-23 21:05:41
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Note

The execution time limit for this problem is 7s.
Also, using a fast language is recommended. (AC has been confirmed in C++ and Java.)

Problem Statement

You are given a sequence $A = \{a_i\}$ of length $N$.
Answer $Q$ queries. Each query is given in the following format.

  • $l \ r$
    • Find the minimum inversion number of $A$ when changing $a_l,a_{l+1},\dots,a_r$ to any integers between $1$ and $N$, inclusive.
    • Each element may be changed to a different value; they do not all need to be the same value. An element may also keep the same value as before the change.

The inversion number of $A$ is the number of pairs $(i,j) \ (1 \leq i < j \leq N)$ satisfying $a_i > a_j$. Note that the queries are independent, and the modified sequence is restored to the original each time.

Input

$N\ Q$
$a_1 \dots a_N$
$l_1 \ r_1$
$\vdots$
$l_Q \ r_Q$

  • All inputs are integers.
  • $1 \leq N,Q \leq 2 \times 10^4$
  • $1 \leq a_i \leq N$
  • $1 \leq l_i \leq r_i \leq N$

Output

On the $i$-th line, output the answer to the $i$-th query.

Sample

Sample 1
Input
5 3
3 1 1 4 2
2 3
5 5
1 5
Output
4
2
0

In the first query, for example, setting $a_2 = 2, \ a_3 = 3$ makes the inversion number 4, which is the minimum.
In the second query, for example, setting $a_5 = 5$ makes the inversion number 2, which is the minimum.
In the third query, for example, setting $a_1 = a_2 = \cdots = a_5 = 1$ makes the inversion number 0, which is the minimum.

Sample 2
Input
4 4
4 3 2 1
1 1
2 2
3 3
4 4
Output
3
4
4
3

Sample 3
Input
10 10
9 7 7 10 9 8 1 3 2 9
5 6
3 9
3 10
2 5
8 9
6 8
1 2
2 4
10 10
2 7
Output
24
1
1
12
15
15
17
15
25
9

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