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 <bits/stdc++.h>
using namespace std;


int main(){
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    
    int n, q;
    int i, j;
    // vector <int> c;
    // vector <int> l;
    // vector <int> r;
        
    cin >> n >> q;

    int *c = new int[n];
    int *r = new int[q];
    int *l = new int[q];

    int a, b;

    for(i = 0; i < n; ++i){
        // cin >> a;
        // c.push_back(a);
        cin >> c[i];
    }

    for(i = 0; i < q; ++i){
        // cin >> a >> b;
        // l.push_back(a);
        // r.push_back(b);
        cin >> l[i] >> r[i];
    }
    
    int cnt;
    // vector <bool> color(n);
    vector <int> color_num;
    bool *color = new bool[n];

    for(j = 0; j < n; ++j) color[j] = false;
 

    for(i = 0; i < q; ++i){
        cnt = 0;

        for(j = l[i] - 1 ; j <= r[i] - 1; ++j){
            if(color[c[j]] == false){
                color[c[j]] = true;    
                cnt++;
            }
        }

        // for(j = 0; j < n; ++j){
        //      color[j] = false;
        // }

//        color_num.push_back(cnt);
        cout << cnt << endl;
    }

//    for(int i = 0; i < q; i++) cout << color_num[i] << endl;

    return 0;
}