Microsoft Q# Coding Contest - Summer 2018

15 problems from Microsoft Q# Coding Contest - Summer 2018 (contest 1002), difficulty 800-1900. 15/15 solutions verified against sample I/O.

15 items

Microsoft Q# Coding Contest - Summer 2018

Special | 15 problems | 15/15 verified | Difficulty 800-1900 | 16m 9s

#	Problem	Rating	Tags	Accepted	Time	✓
A1	Generate superposition of all basis states	800	*special	929	59s	✓
A2	Generate superposition of zero state and a basis state	1300	*special	570	1m 4s	✓
A3	Generate superposition of two basis states	1500	*special	483	1m 9s	✓
A4	Generate W state	1900	*special	274	1m 24s	✓
B1	Distinguish zero state and W state	1300	*special	488	56s	✓
B2	Distinguish GHZ state and W state	1600	*special	455	1m 3s	✓
B3	Distinguish four 2-qubit states	1600	*special	421	1m 10s	✓
B4	Distinguish four 2-qubit states - 2	1700	*special	317	56s	✓
C1	Distinguish zero state and plus state with minimum error	1700	*special	309	1m 12s	✓
C2	Distinguish zero state and plus state without errors	1800	*special	273	1m 15s	✓
D1	Oracle for f(x) = b * x mod 2	1200	*special	418	50s	✓
D2	Oracle for f(x) = b * x + (1 - b) * (1 - x) mod 2	1300	*special	390	1m 5s	✓
D3	Oracle for majority function	1600	*special	341	1m 8s	✓
E1	Bernstein-Vazirani algorithm	1500	*special	329	51s	✓
E2	Another array reconstruction algorithm	1900	*special	209	1m 7s	✓

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002E2 - Another array reconstruction algorithm

We are given a black-box quantum operation that acts on N input qubits plus one auxiliary qubit. Internally, this operation encodes a hidden binary array of length N.

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002E1 - Bernstein-Vazirani algorithm

We are interacting with an oracle that hides a binary string of length $N$. Each position in this hidden string is either 0 or 1. The oracle does not reveal the string directly.

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002D3 - Oracle for majority function

We are working in a quantum setting where three input qubits represent a binary vector of length three, and an additional qubit acts as an output register.

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002D2 - Oracle for f(x) = b * x + (1 - b) * (1 - x) mod 2

We are given a small quantum circuit setting where the input consists of an $N$-qubit register $x$, a single target qubit $y$, and a classical binary vector $b$ of length $N$.

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002C2 - Distinguish zero state and plus state without errors

We are given a single qubit guaranteed to be in one of two possible pure states. One state is the classical basis state $ The output of the operation must be one of three integers.

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002D1 - Oracle for f(x) = b * x mod 2

We are given a very small quantum system consisting of two parts: an input register of N qubits and a single output qubit. Alongside this, we are given a classical binary vector b of length N.

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002C1 - Distinguish zero state and plus state with minimum error

We are given a single qubit that is prepared in one of two possible pure states with equal probability. One of them is the computational basis state $ The task is not to deterministically identify the state, but to implement a quantum procedure that produces a classical bit…

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002B3 - Distinguish four 2-qubit states

We are given a system of two qubits that is guaranteed to be in one of four mutually orthogonal entangled states. These states form a complete basis for two-qubit space, so exactly one of them is present, and the task is to identify which one.

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002B4 - Distinguish four 2-qubit states - 2

We are given a 2-qubit system that is guaranteed to be in exactly one of four mutually orthogonal quantum states. Each of these states is a different encoding of a two-bit piece of information, but not in the standard computational basis.

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002A4 - Generate W state

We are working with a register of $N = 2^k$ qubits, where $k le 4$, so $N le 16$. The system starts in the all-zero computational basis state, meaning every qubit is in $ A W state over $N$ qubits is a uniform superposition of all basis states that contain exactly one qubit in…

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002B2 - Distinguish GHZ state and W state

We are given a small system of qubits, at most eight of them, prepared in one of two highly structured quantum states. One of them is the GHZ state, which behaves like a perfect global correlation between all qubits being simultaneously zero or simultaneously one when measured.

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002B1 - Distinguish zero state and W state

We are given a very small system of qubits, at most eight of them, and the system is guaranteed to be prepared in exactly one of two highly structured quantum states.

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002A3 - Generate superposition of two basis states

We are working in a quantum setting where an initial register of $N le 8$ qubits starts in the all-zero computational basis state. Alongside this register, we are given two classical bitstrings of equal length, each describing a valid basis state on these qubits.

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002A2 - Generate superposition of zero state and a basis state

We start with a register of up to eight qubits, all initialized in the all-zero computational basis state. Alongside this, we are given a classical description of another basis state as a boolean array, where each entry indicates whether the corresponding qubit should be in…

Practice › Codeforces Solutions › Microsoft Q# Coding Contest - Summer 2018 ›

CF 1002A1 - Generate superposition of all basis states

We start with a system of N independent two-level quantum bits, all initially in the state corresponding to zero. In computational terms, this is the single basis state where every qubit is 0.