NYJC 2026 Prelim P1

This document consists of 12 printed pages. © NYJC 2026 [Turn over NANYANG JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATIONS Higher 2 COMPUTING 9569/01 Paper 1 Written 15 September 2026 3 hours READ THESE INSTRUCTIONS FIRST An answer booklet will be provided with this question paper. You should follow the instructions on the front cover of the answer booklet. If you need additional answer paper ask the invigilator for a continuation booklet. Answer all questions. Approved calculators are allowed. The number of marks is given in brackets [ ] at the end of each question or part question. The total number of marks for this paper is 100.

2 9569/01/2026 1 A wildlife rescue centre is developing a program to manage the animals under its care. Birds, mammals, and reptiles are cared for at the centre. For all animals, the data that will be stored include: • Animal ID • Name of the animal • Age of the animal • Health status (Healthy/Sick) • Weight of the animal (in kg). For birds, the additional data stored include: • Wingspan • Flighted (whether the bird is capable of flight - True/False) • Seed proportion • Insect proportion. For mammals, the additional data stored include: • Body temperature • Nocturnal (True/False) • Number of daily feeding sessions. For reptiles, the additional data stored include: • Preferred temperature • Venomous (True/False) • Food serving temperature. When managing an animal: • health status can be retrieved or updated • daily food requirement is calculated based on the animal's weight and a given body condition score (measured on a scale of 1 to 9). When food requirements are calculated: • for a bird, it takes into consideration the seed and insect proportions • for a mammal, it takes into consideration the number of daily feeding sessions • for a reptile, it takes into consideration the food serving temperature. Object-oriented programming will be used to model the animals.

3 9569/01/2026 [Turn over (a) Draw a class diagram that shows the following for the system described above. • the superclass • any subclasses • inheritance • properties • appropriate methods. [8] (b) Explain how encapsulation prevents an animal’s health status or weight from being inadvertently modified. [2] (c) Explain how polymorphism allows more animal types to be added to the program without changing the implementation of animal feeding. [2] A developer suggests moving the Wingspan data into the base Animal class so it can be accessed by all animal subclasses. (d) Suggest why this is a poor application of the inheritance principle. [2]

4 9569/01/2026 2 A satellite sends a calibration signal that lasts for a specified number of milliseconds. The signal is constructed using: • a short pulse lasting 2 milliseconds • a long pulse lasting 5 milliseconds. The order of the pulses matter. The recursive function CountSignals() returns the number of different signals that can be constructed for a given duration (in milliseconds). 01 FUNCTION CountSignals(Duration: INTEGER) RETURNS INTEGER 02 03 IF Duration = 0 THEN 04 RETURN 1 05 ELSE IF Duration < 2 THEN 06 RETURN 0 07 ENDIF 08 09 RETURN CountSignals(Duration - 2) + CountSignals(Duration - 5) 10 11 ENDFUNCTION (a) Draw a complete trace tree for the function call CountSignals(7). Your trace tree should show: • the parameter value for every function call • the value returned by every function call. [3] (b) Explain what might happen if the required signal duration becomes exceedingly large , during the execution of the recursive algorithm. [2] (c) Write an iterative function, CountSignalsIterative(), that returns the same result as CountSignals(). You may use a one-dimensional array in your implementation. [4] (d) Compare the performance of the recursive and iterative algorithms as the required signal duration increases. [2]

5 9569/01/2026 [Turn over 3 A nationwide online retailer, Delivery Zone, processes customer orders every day. The following array of values stored in an array are to be sorted into ascending order. 42 17 68 25 10 55 31 49 For this question, you may assume that the quicksort always selects the first element (left end) of each sub-array as the pivot. (a) Using annotated diagrams, show how quicksort algorithm sorts the values in the array into ascending order. [3] (b) Using annotated diagrams, show how merge sort algorithm sorts the values in the same array into ascending order. [3] The retailer handles two different processes, with specific requirements: • Process A The retailer makes a daily archival of 12 million orders, to be sorted within 10 minutes. • Process B Once a day, the list of orders (already sorted by order number) are handed over to the warehouse for processing. At the warehouse, the orders need to be re-sorted according to order value. A programmer is deciding whether to use quicksort or merge sort for each process. The programmer claims that "Quicksort is always more efficient than Merge Sort! " (c) Discuss whether the programmer's statement is valid. [3] (d) Explain which of the two sorting algorithms is more suitable for each process. You are not allowed to suggest the same algorithm for both processes. Justify your answer by referring to the characteristics of the sorting algorithm and the requirements of the respective processes. [4] (e) Apart from time complexity, state one characteristic of merge sort that may make it more suitable than quicksort in certain applications. [1]

6 9569/01/2026 4 A Pokemon Trainer is developing an application to store the names of Pokemon that have been caught. The names of Pokemon that have been caught are stored in a binary search tree implemented using an array, pokemon_bst. Each element of the array contains three values. pokemon_name is a string, and left_pointer and right_pointer are integers. A pointer value of -1 indicates the null pointer. The variable root stores the array index of the root of the binary search tree. The contents of the array pokemon_bst is shown below. root 2 Index left_pointer pokemon_name right_pointer 0 -1 Bulbasaur -1 1 -1 Eevee -1 2 0 Charmander 3 3 1 Pikachu 4 4 -1 Snorlax 5 5 -1 Squirtle -1 (a) Draw the binary search tree represented by the data in the array pokemon_bst and the value in root. [2] (b) A new Pokemon, Dragonite, is caught and inserted into the pokemon_bst. Copy and complete the table above to show any changes made to the array after this insertion. [2] (c) The application stores the same Pokemon names in both a binary search tree and a hash table. Explain the benefits of storing the Pokemon names in two different data structures instead of only one. In your answer, include one example of an operation that is better suited to each data structure. [3]

7 9569/01/2026 [Turn over (d) The same Pokemon names are stored in an initially empty hash table with 10 locations, indexed from 0 to 9. The procedure insert_pokemon below is used to insert a Pokemon into the hash table. 01 PROCEDURE insert_pokemon(hash_table, Pokemon) 02 03 // ASCII(char) returns the ASCII value of char as integer 04 hash_value ← ASCII(Pokemon[0]) MOD 10 05 index ← hash_value 06 count ← 0 07 08 WHILE hash_table[index] <> "" AND count < 10 09 index ← (index + 1) MOD 10 10 count ← count + 1 11 ENDWHILE 12 13 IF count < 10 THEN 14 hash_table[index] ← Pokemon 15 ENDIF 16 17 ENDPROCEDURE (i) Describe the collision resolution method used by the procedure. [2] (ii) The Pokemon are inserted into the hash table in the following order: Pokemon First letter ASCII Charmander C 67 Pikachu P 80 Bulbasaur B 66 Snorlax S 83 Eeve