Generate superposition of all basis states

You are given N qubits (1 ≤ N ≤ 8) in zero state .

Your task is to generate an equal superposition of all 2^N basis vectors on N qubits:

For example,

• for N = 1, the required state is simply ,
• for N = 2, the required state is .

You have to implement an operation which takes an array of N qubits as an input and has no output. The "output" of the operation is the state in which it leaves the qubits.

Your code should have the following signature:

namespace Solution {
    open Microsoft.Quantum.Primitive;
    open Microsoft.Quantum.Canon;

    operation Solve (qs : Qubit[]) : ()
    {
        body
        {
            // your code here
        }
    }
}