- Time limit: 1.00 s
- Memory limit: 512 MB
You have n coins with positive integer values. The coins are numbered 1,2,\dots,n.
Your task is to process q queries of the form: "if you can use coins a \dots b, what is the smallest sum you cannot produce?"
The first input line has two integers n and q: the number of coins and queries.
The second line has n integers x_1,x_2,\dots,x_n: the value of each coin.
Finally, there are q lines that describe the queries. Each line has two values a and b: you can use coins a \dots b.
Print the answer for each query.
- 1 \le n, q \le 2 \cdot 10^5
- 1 \le x_i \le 10^9
- 1 \le a \le b \le n
5 3 2 9 1 2 7 2 4 4 4 1 5
4 1 6
Explanation: First you can use coins [9,1,2], then coins  and finally coins [2,9,1,2,7].