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 Java (OpenJDK 11.0.6) (judge verdict: Time Limit Exceeded)

import java.util.*;
public class Main{
  public static HashMap<String,Integer> map=new HashMap<String,Integer>();
  public static void main(String[] args)
  {
    Scanner sc=new Scanner(System.in);
  	int n=sc.nextInt();
    int q=sc.nextInt();
    int[] a=new int[n];
    for(int i=0;i<n;i++)
         a[i]=sc.nextInt();
    for(int h=0;h<n;h++)
    {
      for(int g=0;g<n;g++)
      {
          Set<Integer> s1=new HashSet<Integer>();
          for(int j=h;j<=g;j++)
           		s1.add(a[j]);
          StringBuilder d = new StringBuilder(); 
          d.append(h);
          d.append("#");
          d.append(g);
          
          map.put(d.toString(),s1.size());
          
          s1.clear();
      }
    }
    while(q-->0)
    {
      int l=sc.nextInt();
      int r=sc.nextInt();
      StringBuilder s3=new StringBuilder();
          s3.append(l-1);
          s3.append("#");
          s3.append(r-1);
       System.out.println(map.get(s3.toString()));
         
    }
}
 
}