- Time limit: 1.00 s
- Memory limit: 512 MB
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.
- $1 \le n, q \le 2 \cdot 10^5$
- $1 \le x_i \le 10^9$
- $1 \le a \le b \le n$
2 9 1 2 7
Explanation: First you can use coins $[9,1,2]$, then coins $$ and finally coins $[2,9,1,2,7]$.