Mahmoud and Ehab and yet another xor task

Description:

Input:

The first line contains integers n and q (1 ≤ n, q ≤ 10⁵), the number of elements in the array and the number of queries.

The next line contains n integers a₁, a₂, ..., a_n (0 ≤ a_i < 2²⁰), the elements of the array.

The next q lines, each contains integers l and x (1 ≤ l ≤ n, 0 ≤ x < 2²⁰), representing the queries.

Output:

For each query, output its answer modulo 10⁹ + 7 in a newline.

Sample Input:

5 5
0 1 2 3 4
4 3
2 0
3 7
5 7
5 8

Sample Output:

4
2
0
4
0

Sample Input:

3 2
1 1 1
3 1
2 0

Sample Output:

4
2

Note:

The bitwise-xor sum of the empty set is 0 and the bitwise-xor sum of a set containing one element is that element itself.