牛客网暑期ACM多校训练营（第一场） J题详解

牛客网J题在比赛时是通过率最高的一道题，但是这道题对于时间的复杂度要求比较高。在比赛的时候，很多队伍提交的程序都以”运行超时“而结束。那就让我们先来看看这道看似简单的题。

Different Integers

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题目描述

Given a sequence of integers a1, a2, ..., an and q pairs of integers (l1, r1), (l2, r2), ..., (lq, rq), find count(l1, r1), count(l2, r2), ..., count(lq, rq) where count(i, j) is the number of different integers among a 1, a2, ..., ai, aj, aj + 1, ..., an. 

 输入描述：

The input consists of several test cases and is terminated by end-of-file. The first line of each test cases contains two integers n and q. The second line contains n integers a1, a2, ..., an. The i-th of the following q lines contains two integers li and ri.

输出描述：

For each test case, print q integers which denote the result.

备注

* 1 ≤ n, q ≤ 105

* 1 ≤ ai ≤ n

* 1 ≤ li, ri ≤ n

* The number of test cases does not exceed 10.

示例1:

输入

3 2

1 2 1

1 2

1 3

4 1

1 2 3 4

1 3