7. Algorithm design and problem-solving
A section of Computer Science, 2210
Listing 10 of 38 questions
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.
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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
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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.
2210_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
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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.
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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.
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THEORY
2024
Paper 2, Variant 2
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A flowchart checks that values stored in three variables are identical. If they are different, the highest value is stored in all three variables. START STOP Is A = B AND B = C ? Is A >= B OR A >= C ? B A C A Yes Yes No Yes No No Is B >= A AND B >= C ? A B C B A C B C Identify four errors in the flowchart and suggest a correction for each error. You may label each error on the diagram with the corresponding error number. Error 1 Correction Error 2 Correction Error 3 Correction Error 4 Correction
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THEORY
2024
Paper 2, Variant 3
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Members of a litter picking group complete a litter pick every month. Members’ names are stored in one-dimensional (1D) array PickerName Each member stores the weight of the litter they have picked in another one-dimensional (1D) array PickedWeight The weights are in kilograms with one decimal place, for example 8.4 The position of each member’s data in the two arrays is the same. For example, the member stored at index 10 in PickerName and at index 10 in PickedWeight is the same. Every month, there is a small prize awarded to the members of the group who have the two heaviest weights. Certificates are awarded to all members with a pick weight of over three kilograms. Write a program that meets the following requirements: • allows the weight of members’ picks to be input and validated • sorts the arrays PickedWeight and PickerName in descending order of weight • outputs the member names and the pick weights of the members with the two heaviest picks and identifies them as “Best in Group” and “Second best in Group” • stores the names of all the members who will receive a certificate in the array PickerCertificate • outputs a message stating the number of certificates to be printed. 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. You do not need to initialise the data in the array PickerName
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THEORY
2024
Paper 2, Variant 3
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Questions Discovered
38