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: Time Limit Exceeded)

#参考https://qiita.com/takayg1/items/c811bd07c21923d7ec69

#####segfunc#####
def segfunc(x, y):
    return x+y
#################

#####ide_ele初期値#####
ide_ele = 0
#################

class SegTree:
    """
    init(init_val, ide_ele): 配列init_valで初期化 O(N)
    update(k, x): k番目の値をxに更新 O(logN)
    query(l, r): 区間[l, r)をsegfuncしたものを返す O(logN)
    """
    def __init__(self, init_val, segfunc, ide_ele):
        """
        init_val: 配列の初期値
        segfunc: 区間にしたい操作
        ide_ele: 単位元
        n: 要素数
        num: n以上の最小の2のべき乗
        tree: セグメント木(1-index)
        """
        n = len(init_val)
        self.segfunc = segfunc
        self.ide_ele = ide_ele
        self.num = 1 << (n - 1).bit_length()
        self.tree = [ide_ele] * 2 * self.num
        # 配列の値を葉にセット
        for i in range(n):
            self.tree[self.num + i] = init_val[i]
        # 構築していく
        for i in range(self.num - 1, 0, -1):
            self.tree[i] = self.segfunc(self.tree[2 * i], self.tree[2 * i + 1])

    def update(self, k, x):
        """
        k番目の値をxに更新
        k: index(0-index)
        x: update value
        """
        k += self.num
        self.tree[k] = x
        while k > 1:
            self.tree[k >> 1] = self.segfunc(self.tree[k], self.tree[k ^ 1])
            k >>= 1

    def query(self, l, r):
        """
        [l, r)のsegfuncしたものを得る ※区間注意
        l: index(0-index)
        r: index(0-index)
        """
        res = self.ide_ele

        l += self.num
        r += self.num
        while l < r:
            if l & 1:
                res = self.segfunc(res, self.tree[l])
                l += 1
            if r & 1:
                res = self.segfunc(res, self.tree[r - 1])
            l >>= 1
            r >>= 1
        return res

#%%

def function():
    N, Q = map(int, input().split())
    c = list(map(int, input().split()))
    lrs = [list(map(lambda x:int(x)-1, input().split())) for i in range(Q)]
    
    for i in range(len(lrs)):
        lrs[i].append(i)
    
    right_edge = [-1]*(N+1)
    seg = SegTree([0]*(N+1), segfunc, ide_ele)
    # =============================================================================
    # print(seg.tree[1])
    # print(seg.query(0,7))
    # seg.update(0,100)
    # print(seg.tree)
    # =============================================================================
    
    lrs = sorted(lrs, key = lambda x:x[1])
    order_num = 0
    answer = [[] for _ in range(Q)]
    for i, c_o in enumerate(c):
        if right_edge[c_o] >= 0:
            seg.update(right_edge[c_o], 0)
        right_edge[c_o] = i
        seg.update(i, 1)
        
        while order_num < Q:
            if lrs[order_num][1] == i:
                answer[order_num] = [order_num,seg.query(lrs[order_num][0],lrs[order_num][1]+1)]
                order_num += 1
            else:
                break
    
    answer = sorted(answer,key=lambda x: lrs[x[0]][2])
    
    for i in range(len(answer)):
        print(answer[i][1])
        
if __name__ == '__main__':
    function()