Niuniu has recently learned how to use Gaussian elimination to solve systems of linear equations.
Given n and a[i], where n is a power of 2, let's consider an n x n matrix A.
The index of A[i][j] and a[i] are numbered from 0.
The element A[i][j] satisfies A[i][j] = a[i
xor j],
https://en.wikipedia.org/wiki/Bitwise_operation#XOR
Let p = 1000000007.
Consider the equation
A x = b (mod p)
where A is an n x n matrix, and x and b are both n x 1 row vector.
Given n, a[i], b[i], you need to solve the x.
For example, when n = 4, the equations look like
A[0][0]*x[0] + A[0][1]*x[1] + A[0][2]*x[2] + A[0][3]*x[3] = b[0] (mod p)
A[1][0]*x[0] + A[1][1]*x[1] + A[1][2]*x[2] + A[1][3]*x[3] = b[1] (mod p)
A[2][0]*x[0] + A[2][1]*x[1] + A[2][2]*x[2] + A[2][3]*x[3] = b[2] (mod p)
A[3][0]*x[0] + A[3][1]*x[1] + A[3][2]*x[2] + A[3][3]*x[3] = b[3] (mod p)
and the matrix A can be decided by the array a.
It is guaranteed that there is a unique solution x for these equations.