Ex6 2

$\def\abs#1{|#1|}\def\i{\mathbf {i}}\def\ket#1{|{#1}\rangle}\def\bra#1{\langle{#1}|}\def\braket#1#2{\langle{#1}|{#2}\rangle}\def\tr{\mathord{\mbox{tr}}}\mathbf{Exercise\ 6.2}$

a) Construct a classical boolean circuit with $3$ input bits and $2$ output bits that computes as a $2$-bit binary number the number of $1$ bits in the input.

b) Convert your circuit into a classical reversible one.

c) Give an equivalent quantum circuit.