I have to sort an array using a sorting algorithm and show in which index the values were originally placed. (see expected result vs actual result: https://i.imgur.com/GpIpkPE.png).

I managed to sort correctly the values. BUT the index is HALF correct? Which is confusing me.

    public static void sortNumbers(double[] averageNotes) {

        for (int i = 0; i < averageNotes.length; i  ) {
            double max = averageNotes[i];
            int maxId = i;

            for (int j = i 1; j < averageNotes.length; j  ) {
                if (averageNotes[j] > max) {
                    max = averageNotes[j];
                    maxId = j;

                }
            }
            double temp = averageNotes[i];
            averageNotes[i] = max;
            averageNotes[maxId] = temp;
            System.out.println(averageNotes[i]   " ("   maxId   ")");
        }

Any help is highly appreciated. Thank you.

CodePudding user response：

Use an extra array for your indices and sort simultaneously:

public static void sortNumbers(double[] averageNotes) {
    //create an array for your indices
    int[] indices = new int[averageNotes.length];

    //fill indices
    for (int i = 0; i < averageNotes.length; i  ) {
        indices[i] = i;
    }

    //sort both arrays simultaneously
    for (int i = 0; i < averageNotes.length; i  ) {
        for (int j = i 1; j < averageNotes.length; j  ) {
            if (averageNotes[i] < averageNotes[j]) {
                double temp = averageNotes[i];
                averageNotes[i] = averageNotes[j];
                averageNotes[j] = temp;
                
                int t = indices[i];
                indices[i] = indices[j];
                indices[j] = t;
            }
        }
    }

    //print
    for (int i = 0; i < averageNotes.length; i  ) {
        System.out.println(averageNotes[i]   " ("   indices[i]   ")");
    }
}