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 PyPy3 (7.3.0) (judge verdict: Runtime Error)

from copy import deepcopy

if __name__ == '__main__':
    N, Q = map(int, input().split())
    C = list(map(int, input().split()))
    LR = []
    for i in range(Q):
        LR.append(tuple(map(int, input().split())))
    ACC = []
    ACC.append({})
    hash = {} 
    for c in C:
        if c in hash:
            hash[c] += 1
        else:
            hash[c] = 1 
        ACC.append(deepcopy(hash))
    for l, r in LR:
        head = ACC[l-1]
        tail = ACC[r]
        head_set = set(head.keys())
        tail_set = set(tail.keys())
        only_have_tail = tail_set - head_set
        kind_cnt = len(only_have_tail)
        # delta = r - (l - 1)
        for key in have_each:
            if head[key] == tail[key]:
                pass
            else:
                kind_cnt += 1
        
        print(kind_cnt)