Problem:
Score : 600 points

Problem Statement

We have N colored balls arranged in a row from left to right; the color of the i-th ball from the left is c_i.

You are given Q queries. The i-th query is as follows: how many different colors do the l_i-th through r_i-th balls from the left have?

Constraints

1\leq N,Q \leq 5 \times 10^5

1\leq c_i \leq N

1\leq l_i \leq r_i \leq N

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N Q
c_1 c_2 \cdots c_N
l_1 r_1
l_2 r_2
:
l_Q r_Q

Output

Print Q lines. The i-th line should contain the response to the i-th query.

Sample Input 1

4 3
1 2 1 3
1 3
2 4
3 3

Sample Output 1

2
3
1

The 1-st, 2-nd, and 3-rd balls from the left have the colors 1, 2, and 1 - two different colors.

The 2-st, 3-rd, and 4-th balls from the left have the colors 2, 1, and 3 - three different colors.

The 3-rd ball from the left has the color 1 - just one color.

Sample Input 2

10 10
2 5 6 5 2 1 7 9 7 2
5 5
2 4
6 7
2 2
7 8
7 9
1 8
6 9
8 10
6 8

Sample Output 2

1
2
2
1
2
2
6
3
3
3

Solution in Rust (1.42.0) (judge verdict: Wrong Answer)

use proconio::input;
#[allow(unused_imports)]
use proconio::marker::{Bytes, Chars};
#[allow(unused_imports)]
use std::cmp::{min, max};
use std::collections::HashMap;

fn main() {
	input! {
		n: usize,
		q: usize,
		c: [usize; n],
		lr: [(usize, usize); q],
	}

	let mut v: Vec<HashMap<usize, usize>> = vec![HashMap::new(); n];

	v[0].insert(c[0], 1);
	for i in 1..n {
		for j in 0..=i {
			let count = v[i].entry(c[j]).or_insert(0);
			*count += 1;
		}
	}

	for i in 0..q {
		let mut count = 0;
		for (rk, rv) in &v[lr[i].1-1] {
			for (lk, lv) in &v[lr[i].0-1] {
				if lk == rk {
					if lv < rv {
						count += 1;
					}
					else {

					}
				}
				else {
					count += 1;
				}
			}
		}
		println!("{}", count);
	}
}