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 1.8.0) (judge verdict: Time Limit Exceeded)

import java.util.*;
import java.io.*;
 
public class Main {
	public static void main(String args[] ) throws Exception {


		InputStreamReader s = new InputStreamReader(System.in) ; 

		int[] arr = getdata ( 2 , s ) ;
		int N = arr[0] ; 
		int Q = arr[1] ;

		arr = getdata ( N , s ) ;
		List<Map<Integer,Integer>> list = new ArrayList<>() ; 
		list.add ( new HashMap<>() ) ;
		for ( int j=0 ; j<arr.length ; j++ ) {
			int r = arr[j] ;
			Map<Integer,Integer> map2 = new HashMap<>( list.get(list.size()-1) ) ; 
			map2.put( r  , map2.getOrDefault( r , 0 ) + 1 ) ;
			list.add ( map2 ) ;
		}

		for ( int j=0 ; j<Q  ;j++ ) {
			arr = getdata ( 2 , s ) ;
			int l = arr[0] ;
			int r = arr[1] ;

			int c = 0 ;

			for ( int k : list.get(r).keySet() ) {
				if ( ! list.get(l-1).containsKey( k ) ) {
					c ++ ;
				} 
				else if ( list.get(r).get(k).intValue() > list.get(l-1).getOrDefault( k , 0 ) ) {
					c ++ ;
				}
			}
			System.out.println( c ) ;

		}
	}

	public static int[] getdata ( int c , InputStreamReader s ) throws Exception { 
		int[] arr = new int[c] ;
		int idx= 0 ;
		int d  = 0 ;

		while ( true ) {
			int v = s.read();

			if ( v == 32 ) {
				if ( d != 0 ) {
					arr[idx] = d ; 
					d = 0 ; 
					idx++ ;
				}

			} else if ( v <=15 ) {
				break ;
			} else {
				d = d * 10 + ( v - 49 + 1 ) ;
			}
		}
		arr[idx] = d ;
		return arr ;
	}
}