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: Runtime Error)

#![allow(
  non_snake_case,
  unused_variables,
  unused_assignments,
  unused_mut,
  unused_imports,
  dead_code
)]
//use proconio::fastout;
use proconio::input;
use proconio::marker::*;
use std::cmp::*;
use std::collections::*;
//use std::collections::VecDeque;

fn main() {
  input! {
     N:usize,Q:usize,
     c:[usize;N],
     lr:[(Usize1,Usize1);Q]
  }
  // 各色の最初の位置と最後の位置を記録する。
  //  let mut sta = HashMap::new();
  let mut ans = vec![0i64; N];
  let mut last = vec![N; N];
  let mut prev = vec![N; N];
  for i in 0..N {
    let v = last[c[i]];
    if v < N {
      prev[i] = v;
    } else {
      last[c[i]] = i;
    }
  }
  //println!("p{:?}", prev);
  for i in 0..Q {
    let (l, r) = lr[i];
    let mut ans = r - l + 1;
    for j in l..=r {
      if prev[j] !=N && prev[j] >= l {
        ans -= 1;
      }
    }
    println!("{}", ans);
  }
}