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 C (GCC 9.2.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <math.h>
#include <assert.h>
#include <stdlib.h>

int main(void)
{

	int n,q;
	scanf("%d %d",&n,&q);
	
	int *c;
	c=(int *)malloc(sizeof(int)*(n));
	int l,r;
	
	int *answer;
	answer=(int *)malloc(sizeof(int)*q);
	int i,j,k;
	int count;
	for(i=0;i<n;i++)
	{
		scanf("%d",&c[i]);
	}
	for(i=0;i<q;i++)
	{
		count=0;
		scanf("%d %d",&l,&r);
		for(k=0;k<n;k++)
		{
			for(j=l-1;j<r;j++)
			{
				if(k==c[j])
				{
					count++;
					break;
				}
			}
		}
		answer[i]=count;
	}
	for(i=0;i<q;i++)
	{
		printf("%d\n",answer[i]);
	}
	
	free(answer);
	free(c);
	return 0;
}