Grading Students Algorithm

In this article, I'll be describing how I solved the Grading Students Challenge on HackerRank using Python 3.

This challenge is part of the Implementation challenges in the Algorithm section on HackerRank.

Problem 🎲

HackerLand University has the following grading policy:

• Every student receives a grade in the inclusive range from 0 to 100.
• Any grade less than 40 is a failing grade.

Sam is a professor at the university and likes to round each student's grade according to these rules:

• If the difference between the grade and the next multiple of 5 is less than 3, round grade up to the next multiple of 5.
• If the value of grade is less than 38, no rounding occurs as the result will still be a failing grade.

Example

• grade = 84 round to 85 (85 - 84 is less than 3)
• grade = 29 do not round (result is less than 40)
• grade = 57 do not round (60 - 57 is 3 or higher)

Given the initial value of grade for each of Sam's n students, write code to automate the rounding process.

Function Description

Complete the function gradingStudents.

gradingStudents has the following parameter(s):

• int grades[n]: the grades before rounding

Returns

• int[n]: the grades after rounding as appropriate

Input Format

The first line contains a single integer, n, the number of students. Each line i of the n subsequent lines contains a single integer, grades[i].

Constraints

• 1 ≤ n ≤ 60
• 0 ≤ grades[i] ≤ 100

Samle Input:

73
67
38
33

Samle Ouput:

75
67
40
33

Explanation:

1. Student 1 received a 73, and the next multiple of 5 from 73 is 76. Since 75-73 < 3, the student's grade is rounded to 75.
2. Student 2 received a 67, and the next multiple of 5 from 67 is 70. Since 70 - 67 = 3, the grade will not be modified and the student's final grade is 67.
3. Student 3 received a 38, and the next multiple of 5 from 38 is 40. Since 40 - 38 < 3, the student's grade will be rounded to 40.
4. Student 4 received a grade below 33, so the grade will not be modified and the student's final grade is 33.

Solution 🔎

We'll code up logic for all conditions in the problem.

Let's assume grades = [73, 67, 38, 33] to test our solution.

def gradingStudents(grades):
    # Write your code here

Step 1️⃣ : Loop through the array of grades

We'll need to apply or grading logic to every grade in the array by looping and storing the results in a new empty array called `result.

def gradingStudents(grades):
    result = []
    for grade in grades:

Step 2️⃣: Developing the grading logic using conditional statements. ⚙️

For us to track how each grade relates to a multiple of 5, we use:

    tmp = grade % 5

• If the grade is less than 38, no rounding occurs, and add the grade to the results array:

    if grade < 38:
        result.append(grade)

• If the difference between the grade and the next multiple of 5 is less than 3, round grade up to the next multiple of 5.
• If the difference between the grade and the next multiple of 5 is greater than or equal to 3, the grade will not be modified and the student's final grade will be returned.
• Add the modified grades to the results array.

    elif (5 - tmp) < 3:
        result.append(grade + 5 - tmp)
    elif (5 - tmp) == 3:
        result.append(grade)

• else return all other grades outside this condition and add them to the results array.

        else:
            result.append(grade)

• Finally, return our completed results array.

    return result

Full code:

def gradingStudents(grades):
    result = []
    # Write your code here
    for grade in grades:
        tmp = grade % 5
        if grade < 38:
            result.append(grade)
        elif (5 - tmp) < 3:
            result.append(grade + 5 - tmp)
        elif (5 - tmp) == 3:
            result.append(grade) 
        else:
            result.append(grade)
    return result  


gradingStudents([73, 67, 38, 33])
>> [75, 67, 38, 33]

Hope this helps with understanding this challenge. Happy Coding!👨🏽‍💻