7. Algorithm design and problem-solving
A section of Computer Science, 0478
Listing 10 of 61 questions
Four descriptions and five pseudocode statements are shown. Draw one line to link each description to its most appropriate pseudocode statement. Not all pseudocode statements will be used. Description Pseudocode statement a statement to count a statement to total a statement to start a pre-condition loop a statement to start a post-condition loop FOR Count 1 TO 10 Value Value + NewValue WHILE Value > 10 DO Value Value + 1 REPEAT Write an algorithm in pseudocode, using a single loop, to output the average of 50 numbers that have been stored in the array Number
0478_m23_qp_22
THEORY
2023
Paper 2, Variant 2
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Students in a class are recording the amount of time in minutes spent in front of a screen for each day of the week. The one-dimensional (1D) array StudentName contains the names of the students in the class. The two-dimensional (2D) array ScreenTime is used to input the number of minutes on each day spent in front of a screen. The position of each student’s data in the two arrays is the same. For example, the student stored at index 10 in StudentName and ScreenTime is the same. The variable ClassSize contains the number of students in the class. Write a program that meets these requirements: • allows all the students to enter their daily minutes of screen times for the past week • calculates the total number of minutes of screen time for each student in the week • counts, for each student, the number of days with more than 300 minutes of screen time • calculates the average weekly minutes of screen time for the whole class • finds the student with the lowest weekly minutes of screen time • outputs for each student: – name – total week’s screen time in hours and minutes – number of days with more than 300 minutes of screen time • outputs the average weekly minutes of screen time for the whole class • outputs the name of the student with the lowest weekly screen time. You must use pseudocode or program code and add comments to explain how your code works. All inputs and outputs must contain suitable messages. Assume that the array StudentName and the variable ClassSize already contain the required data. You do not need to declare any arrays or variables; you may assume that this has already been done.
0478_m24_qp_22
THEORY
2024
Paper 2, Variant 2
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A one-dimensional (1D) array Days contains the names of the days of the week. A two-dimensional (2D) array Readings is used to store 24 temperature readings, taken once an hour, for each of the seven days of the week. A 1D array AverageTemp is used to store the average temperature for each day of the week. The position of any day’s data is the same in all three arrays. For example, if Wednesday is in index 4 of Days, Wednesday’s temperature readings are in index 4 of Readings and Wednesday’s average temperature is in index 4 of AverageTemp The temperature readings are in Celsius to one decimal place. Temperatures can only be from –20.0 °C to +50.0 °C inclusive. Write a program that meets the following requirements: • input and validate the hourly temperatures for one week • calculate and store the average temperature for each day of the week • calculate the average temperature for the whole week • convert all the average temperatures from Celsius to Fahrenheit by using the formula Fahrenheit = Celsius * 9 / 5 + 32 • output the average temperature in Celsius and in Fahrenheit for each day • output the overall average temperature in Celsius and in Fahrenheit for the whole week. You must use pseudocode or program code and add comments to explain how your code works. You do not need to declare any arrays, variables or constants; you may assume that this has already been done. All inputs and outputs must contain suitable messages. All data output must be rounded to one decimal place. You will need to initialise and populate the array Days at the start of the program.
0478_s23_qp_21
THEORY
2023
Paper 2, Variant 1
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An algorithm has been written in pseudocode to find and display the maximum and minimum values in an array of 1000 positive numbers. The array List starts at index 1 01 Max List 02 Min List 03 FOR Counter 2 TO 1000 04 IF List Selection statement Iteration statement Identify the line numbers of the three errors in the pseudocode and suggest a correction for each error. Error 1 line number Correction Error 2 line number Correction Error 3 line number Correction
0478_s24_qp_22
THEORY
2024
Paper 2, Variant 2
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Four pseudocode statements and five pseudocode uses are shown. Draw one line to link each pseudocode statement to the most appropriate pseudocode use. Not all pseudocode uses will be required. Pseudocode statement CALL Colour(NewColour) Value (A1 + A2 + A3) / 3 Loop1 Loop1 + 1 IF Count > 7 THEN X1 Pseudocode use counting finding an average totalling using a conditional statement using a procedure A one‑dimensional (1D) array called Temperatures has 25 elements beginning at index 1. It holds values that range between –20 and 100 inclusive. Write a pseudocode algorithm using a single loop to find the lowest value in this array and output the result only once. You do not need to declare or populate this array.
0478_w23_qp_22
THEORY
2023
Paper 2, Variant 2
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A weather station takes temperature readings once an hour for a week. These temperatures are stored in a two-dimensional (2D) array Temperatures Each column contains 24 readings for a single day. The first temperature is recorded at 00:00 and the final temperature at 23:00. There are seven columns, one for each day of the week, starting with Monday and ending with Sunday. The variables MaxDay, MinDay and AvDay are used to store the maximum, minimum, and average temperatures for a day. The variables MaxWeek, MinWeek and AvWeek are used to store the maximum, minimum, and average temperatures for the week. The array has already been set up and the data stored. Write a program that meets the following requirements: • finds the maximum and minimum temperatures for each day • calculates the average temperature for each day • outputs for each day: – name of the day, for example Monday – maximum temperature – minimum temperature – average temperature • finds the maximum and minimum temperatures for the week • calculates the average temperature for the week • outputs: – maximum temperature for the week – minimum temperature for the week – average temperature for the week. All temperatures output must be rounded to two decimal places. You must use pseudocode or program code and add comments to explain how your code works. All inputs and outputs must contain suitable messages. You do not need to declare any arrays or variables; you may assume that this has already been done. You do not need to initialise the data in the array Temperatures
0478_w23_qp_23
THEORY
2023
Paper 2, Variant 3
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This pseudocode algorithm is intended to sort a pre-populated one-dimensional (1D) array named ItemList into alphabetical order using a bubble sort. 01 DECLARE ItemList : ARRAY[1:100] OF STRING 02 DECLARE Counter : STRING 03 DECLARE Limit : INTEGER 04 DECLARE Pass : INTEGER 05 DECLARE Swapped : BOOLEAN 06 DECLARE Temp : STRING 07 Limit 08 Pass 09 Temp TRUE 10 WHILE Swapped = TRUE OR Pass ItemList[Counter + 1] 14 THEN 15 Temp ItemList 16 ItemList ItemList[Counter + 1] 17 ItemList Temp 18 Swapped TRUE 19 ENDCASE 20 Pass Pass + 1 21 NEXT Counter 22 ENDWHILE Identify the line numbers of five errors in the pseudocode and suggest a correction for each error. Error 1 line number Correction Error 2 line number Correction Error 3 line number Correction Error 4 line number Correction Error 5 line number Correction A bubble sort algorithm can be written to include features that make it more efficient. Explain why the corrected bubble sort algorithm is efficient.
0478_w24_qp_22
THEORY
2024
Paper 2, Variant 2
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A one-dimensional (1D) array Rooms contains the names of up to 20 rooms in a house. A two-dimensional (2D) array Dimensions is used to store the length, width and area of each room. The position of any room’s data is the same in both arrays. For example, the data in index 5 of Dimensions belongs to the room in index 5 of Rooms The variable Number stores the number of rooms for which data is to be input. There must be at least 3 rooms but no more than 20. Write a program that meets the following requirements: • allows the number of rooms for which data is required to be input, stored and validated • allows the name of the room and the length and width of the room, in metres, to be entered and stored • allows the area of each room to be calculated as length multiplied by width and stored as square metres rounded to two decimal places • calculates the average size of all the rooms by area, in square metres, rounded to two decimal places • finds the largest room and smallest room by area • outputs the names of all rooms with their dimensions and area • outputs the names of the largest room and smallest room by area • outputs the total area of the house and the average size of all the rooms by area. You must use pseudocode or program code and add comments to explain how your code works. You do not need to declare any arrays or variables; you may assume that this has already been done. All inputs and outputs must contain suitable messages.
0478_w24_qp_22
THEORY
2024
Paper 2, Variant 2
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A linear search and a bubble sort are standard methods of solution. Fifty numbers are already stored in the array Values[1:50] Write an algorithm in pseudocode to input a number, MyNumber, and use a linear search to test if that number is stored in the array. If the number is found in the array, the position in the array is output. If the number is not found in the array, “Not found” is output. Write an algorithm in pseudocode to sort the array Values[1:50] into ascending order using a bubble sort.
0478_m24_qp_22
THEORY
2024
Paper 2, Variant 2
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A one-dimensional (1D) array Teams contains the names of 10 football teams in a local league. A two-dimensional (2D) array Results stores, for each team, the total number of: • games won • games drawn • games lost • points. The position of any team’s data is the same in both arrays. For example the data in index 3 of Results belongs to the team in index 3 of Teams The array data will be used to find the current leader of the league. The variable Played stores the number of games played by each team. Each team plays the same number of games. Write a program that meets the following requirements: • allows the number of games played to be input and stored, with a maximum of 18 games • allows the names of the teams to be input and stored • allows the number of games won, drawn and lost to be input and stored for each team • validates the number of games played and the number of games won, drawn or lost against the number of games played • calculates and stores the number of points for each team using three points for a win and one point for a draw; there are no points for a loss • sorts the array Results into descending order of number of points, ensuring the corresponding parallel array Teams is kept in the same order • determines how many teams have the highest number of points • outputs the nameof the winning teamalong with the number of points achieved. You must use pseudocode or program code and add comments to explain how your code works. You do not need to declare any arrays, variables or constants; you may assume that this has already been done. All inputs and outputs must contain suitable messages.
0478_s24_qp_23
THEORY
2024
Paper 2, Variant 3
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Questions Discovered
61