SDE - Intern

You are given a list of a repeated set of integers. Your task for the problem is to return a list of the given elements in decreasing sorted order of their frequency of repetition in the given list with the element with the highest frequency of repetition first and so on.

Note :

If two numbers have the same frequency then keep the one that was present before the other in the original given list (array) first.

For Example :

Input:  arr[] = {2, 5, 2, 8, 5, 6, 8, 8}
Output: arr[] = {8, 8, 8, 2, 2, 5, 5, 6}

Explanation :
When you sort the array based on the decreasing order of the frequency of repetition of integers in the original array, 
you’ll find that the element ‘8’ is the integer with the most repeated values therefore it would be arranged first after which since both 2 and 5 have the same number of repeated 
values in the original array but since the 2 arrived first so we will first arrange 2 and then 5 in our resultant array, while would be the last element after sorting here.

Ninja has been given a program to do basic string compression. For a character that is consecutively repeated more than once, he needs to replace the consecutive duplicate occurrences with the count of repetitions.

Example:

If a string has 'x' repeated 5 times, replace this "xxxxx" with "x5".

The string is compressed only when the repeated character count is more than 1.

Note :

The consecutive count of every character in the input string is less than or equal to 9.

You are given an array ‘ARR’ of size ‘N’ containing each number between 1 and ‘N’ - 1 at least once. There is a single integer value that is present in the array twice. Your task is to find the duplicate integer value present in the array.

For example:

Consider ARR = [1, 2, 3, 4, 4], the duplicate integer value present in the array is 4. Hence, the answer is 4 in this case.

Note :

A duplicate number is always present in the given array.

You are given a positive integer ‘N’. Your task is to print all prime numbers less than or equal to N.

Note: A prime number is a natural number that is divisible only by 1 and itself. Example - 2, 3, 17, etc.

You can assume that the value of N will always be greater than 1. So, the answer will always exist.