July 2018 – Let us code

Sorting the elements by frequency

July 27, 2018adminLeave a comment

Given an array, how do we sort the elements by descending order of their frequency? Also if two elements appear for same number of times, one which appeared first in the input array should be placed first. For example, if A = [7, 6, 1, 7, 1, 3, 6, 6, 2] The output should be…

Comparator and Comparable interfaces in Java

July 26, 2018July 27, 2018adminLeave a comment

In Java there are two ways to impose ordering on objects. One is through Comparator interface, and the other is through Comparable interface. Let us see the similarities and differences between them and when should we use them. If we are defining a class, and we want a natural ordering of a collection of the…