题目描述
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?
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.
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.
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
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
4 3
1 2 1 3
1 3
2 4
3 3
样例输出
2
3
1