[Solved] Jhunjhunwala has taught Programming in Java to the second-year students

Mrs. Jhunjhunwala has taught Programming in Java to the second-year students in ICE college and conducted 3 academic tasks for all the (N) students. Marks are store in a 2-D array but now Mrs. Jhunjhunwala is willing to implement a java program which can accept the 2-D array of marks and return the average marks of Best 2 Academic Tasks of each student. Help her to implement a method public double[] average_marks(double [][] marks)

Input Format

First line reads the number of students N
Next N lines read the marks of each student seperated by space

Constraints

n>0

Output Format

Prints the Avaerage marks of best 2 Academic tasks of N students separated by space

Sample Input 0

2
10.5 2.5 15
5.25 6.75 11.25
Sample Output 0

12.75 9.0

Solution

step-by-step:

1. The average_marks method takes a 2D array marks as input, where marks[i][j] represents the mark obtained by the i-th student in the j-th academic task.
2. It initializes an array averages to store the average marks of each student.
3. For each student, it creates a new Double array sortedMarks that contains the marks of that student, and sorts it in descending order using Arrays.sort(sortedMarks, Collections.reverseOrder()). Note that we can’t directly sort a primitive double array using Collections.reverseOrder(), so we need to convert the double array to a Double array first.
4. It then calculates the sum of the best 2 marks of each student using the sortedMarks array, and divides it by 2 to get the average of the best 2 marks.
5. The method stores the average in the averages array.
6. Once the loop has finished iterating over all the students, the average_marks method returns the averages array.

import java.io.*;
import java.util.*;

public class Main {
    public static double[] average_marks(double[][] marks) {
        int n = marks.length;
        double[] averages = new double[n];
        
        for (int i = 0; i < n; i++) {
            double sum = 0;
            Double[] sortedMarks = new Double[3];
           
            for (int j = 0; j < 3; j++) {
                sortedMarks[j] = marks[i][j];
            }
            // sauravhathi
            Arrays.sort(sortedMarks, Collections.reverseOrder());

            for (int j = 0; j < 2; j++) {
                sum += sortedMarks[j];
            }

            averages[i] = sum / 2;
        }
        
        return averages;
    }

    public static void main(String[] args) throws IOException {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        double[][] marks = new double[n][3];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < 3; j++) {
                marks[i][j] = sc.nextDouble();
            }
        }
        double[] averages = average_marks(marks);
        for (int i = 0; i < n; i++) {
            System.out.print(averages[i] + " ");
        }
    }
}

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