How to sort an array and keep track of the index in java

Question

I am trying to sort (decreasing) an array of integers but keeping track of the original index.

I mean, for example if I have this array:

b[         


        

Answer 1

The following answer provides the main steps to overcome the issue explained in the question without details code provided.

• you can create custom Class that has two attributes value and index. where value is the original attribute value and index is the position before sorting.
• create an ArrayList of this Class.
• add the new objects of the created Class with the wanted value and index.

Note: one possible way to set the index value is to iterate through the Arraylist and set the value of index using loop index.

• sort the Arraylist using specialComparable based on value attribute.

now after sorting you can know the previousindex of any entry by invoking its index attribute.