N7 Education

INPUT = [2, -2, -5, 7, 0] // A collection A=0 B=0 C=0 loop while INPUT.hasNext() A = INPUT.getnext() if (A => 0) then B = INPUT.getnext() end if C = A+B output C end loop

Explain why binary search is almost always more efficient than linear search on ordered values.

In the context of programming, define a flag.

[1]

Given two arrays, ALPHA which contains 10 elements and BETA which contains 20 elements, construct an algorithm to determine whether or not ALPHA is a subset of BETA. That is, if all the items in ALPHA are also in BETA then output “SUBSET” otherwise output “NOT SUBSET”

[7]

561806

Short Answer5 MarksPremium

A futuristic solar-power plant on the planet Mars needs to coordinate the direction of its solar panel arrays throughout the day to ensure they are always facing the sun.

With respect to the planet Mars scenario described, evaluate the use of a centralised system of control in relationship to a distributed system of control.

[5]

25580

Short Answer5 MarksPremium

Just as power laws are applicable to phenomena in nature, so too may they suitably model the structure of networks at scale.

Discuss how power laws can be used to model and predict the evolution of the World Wide Web (WWW) both in terms of the number of documents on the web and the number of hyperlinks between them.

[5]

5231

∇ Triangular Numbers

Short Answer3 MarksPremium

A recursive function tri(n) calculates and returns the sum of the first n natural numbers, also known as the nth triangular number. For example, tri(1), tri(2) and tri(3) return the numbers 1, 3 and 6 respectively. Visually, the tri(n) function could be imagined as one that calculates the number of dots contained within a nabla (a triangle with its tip facing downward) for a specified height n, as shown below.

Construct the function tri(n)

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Ahead of the Stack

Extended Response12 MarksPremium

At the moment marathon runners cross the finishing line of a race, their names are added to a stack called RUNNERS.

For example, a diagram of RUNNERS below indicates “Ellie” has finished first and “Jessie” last. “Jessie” is at the top of the RUNNERS stack.

Using pseudocode, construct an efficient procedure that will search the stack RUNNERS for a name given via standard input. Once the given name is found, output the finishing place of the runner specified as a number. If a name is not found then the procedure should output the message "Runner not found". Assume all names are unique, the number of elements in RUNNERS is unknown and RUNNERS may be emptied during the search process.

[6]

For example, given an input string of "Joel" the procedure will output the number 2 to indicate Joel finished in 2nd place.

Outline why the use of a queue would make this algorithm simpler and more efficient than using a stack.

In the same way as RUNNERS saves each runner's name, another stack called TIMES saves each runner's finishing time as they cross the finish line.

The results of a particular competition where 101 runners successfully finish a race are held in RUNNERS and TIMES. Given an empty 101x2 (row x column) 2D array called RESULTS, write pseudocode such that the first column contains the names of all those runners who finished the race and the second column contains their respective times in ascending rank order.

For example, RESULTS[7][1] should contain the time of the runner who finished in 94th place, that is, having only ran faster than seven people (eighth last).

Using RESULTS, state the single line of pseudocode that represents the name of the runner with the median finishing time.

[1]

772603

Chasing Your Tail

Extended Response11 MarksCommunity

Consider the array implementation of a circular queue illustrated below. Each element in the queue is characterised by both an index and value, indicating the underlying array index and element value respectively.

(i).

By manipulating the circular queue represented above, draw the result of enqueuing letters "C", "A" & "T" (in their provided written order from left to right i.e. x3 separate enqueue operations) followed by one dequeue operation.

Given an array implementation of the circular queue above, state the condition upon which it would be identified as FULL.

(ii).

Describe the key functionality of a circular queue.

Compare and contrast circular queues with linear queues.

Consider the following recursive algorithm, where arr refers to an array type input.

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Short Answer3 MarksPremium

function mystery(arr, i) if i = 0 output "not found" return false if arr[i - 1] = 7 then output i return true else mystery(arr, i - 1) end if end function

State the output of mystery( [3,1,5,7,9,2] , 6 ) and describe what the mystery function generally achieves when the initial inputs for arr and i refer to an array and its corresponding length respectively.

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Short Answer6 MarksCommunity

Construct both a logic diagram and truth table for the following expression:

[6]

NOT A OR B AND C

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Short Answer6 MarksPremium

Given a square 2D array of positive integers called NUMBERS of size 7x7, construct a flow chart to describe an efficient algorithm that returns the sum of the downward diagonal (top left to bottom right).

[6]

For example, according to the algorithm described, the following 2D array would yield the number 22.

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Short Answer2 MarksCommunity

Nominate one suitable sensor for an automatic clothes dryer control system and state it's purpose.

Choose the sequence of control system operations that best represents the process of capturing physical phenomena as input and mapping them through a control system to generate a physical output, in a left-to-right order.

16351

Multiple Choice1 MarkPremium

Logic Operator, Sensor, ADC, DAC, Actuator

Actuator, ADC, Logic operation, DAC, Sensor

Sensor, ADC, Transducer, DAC, Actuator

Sensor, ADC, Logic operation, DAC, Actuator

26410

Multiple Choice1 MarkPremium

If one ASCII character requires 8 bits of memory, select the number of characters which can be stored in 4 bytes.

47622

Extended Response6 MarksPremium

The process of detecting a building fire is carried out by ionisation-type smoke detectors / sensors which are continuously monitoring the flow of ions (current) between two electrically charged plates. If the ion flow between the plates is sufficiently disrupted by smoke, alarms are sounded across the building to alert occupants. If the activated alarms are not turned off within the period of time programmed in system configuration, a message is sent via a fast and reliable fibre optic internet connection to the local fire department’s Emergency Management System (EMS).

Explain relationship between sensors, processor(s) and output transducers in this scenario.

The incomplete control system flow chart below represents the smoke alarm system scenario described above.

Provide appropriate labels to replace X, Y & Z in order to complete the system flowchart above for the scenario described.

Identify two key features of a WAN.

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Short Answer2 MarksPremium

A bank has designed a new online banking service for both their local and international customers. Data will be sent around the world using secure protocols to ensure client banking details are kept safe.

43681

Extended Response13 MarksPremium

Define the term 'data packet'.

Outline how protocols enable successful network communication.

The bank advises that customers do not use the online banking service on public Wi-Fi due to security risks.

With respect to online banking on public Wi-Fi, outline one security risk.

Describe two critical devices required for a public wireless network to function.

Distinguish between time-slicing and priority-based scheduling in relation to how operating systems govern multitasking.

641150

Short Answer4 MarksPremium

Outline the primary function of the Memory Address Register (MAR) in the machine execution cycle.

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Short Answer2 MarksPremium

A group of monkeys are collecting bananas in a jungle. As illustrated below, the jungle is represented by a 3x4 2D array called JUNGLE where each element contains a certain number of bananas. The monkeys collect bananas starting from the top left corner through to the bottom right corner of the jungle. The monkeys can only move right or down at any point in time. Construct an algorithm to output the maximum number of bananas the monkeys can collect.

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Short Answer4 MarksPremium

Describe the purpose of paging in the management of primary memory.

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Short Answer3 MarksPremium