% Grover search algorithm example for Quack!
% by Peter Rohde

quack

% Prepare the input state
init_state(3);
prepare_one(3);

% Apply Hadamard transform
H(1)
H(2)
H(3)

% Apply the oracle
n = input('Which of the four basis states should be tagged by the oracle? ');

if n == 1
	X(1)
	X(2)
	toffoli(1,2,3)
	X(1)
	X(2)
end

if n == 2
	X(2)
	toffoli(1,2,3)
	X(2)
end

if n == 3
	X(1)
	toffoli(1,2,3)
	X(1)
end

if n == 4
	toffoli(1,2,3)
end

% Apply Hadamard transform
H(1)
H(2)

% Apply conditional phase shift
X(1)
X(2)
H(2)
cnot(1,2)
H(2)
X(1)
X(2)

% Apply Hadamard transform
H(1)
H(2)
H(3)

% Measure the output state
disp('Measurement outcomes: ')
disp(Z_measure(1))
disp(Z_measure(2))