The $SWAP$ gate allows you to swap the state of any two qubits. In this exercise, you need to apply it to two qubits given by their indices in an array of qubits; you can access individual qubits of the array as `qs[index of a qubit]`.

@[solution]({
    "id": "multi_qubit_gates__qubit_swap_solution",
    "codePath": "./Solution.qs"
})
