Associate Professional

There is a wedding ceremony at NinjaLand. The bride and groom want everybody to play a game and thus, they have blindfolded the attendees. The people from the bride’s side are holding odd numbers and people from the groom’s side are holding the even numbers. For the game to start quickly, all the bride’s side people should come first, followed by the groom’s side people in the same order.

The attendees of the wedding with their numbers are given in the form of a Singly Linked List, arranged randomly.

A singly linked list is a type of linked list that is unidirectional; that is, it can be traversed in only one direction from head to the last node (tail).

Example:

The attendees holding numbers from 1, 4, 3 are shown: 

As the organizers are busy, you have to arrange all the people by arranging the bride’s side people first followed by the groom’s side people sequentially.

Note:

For the above example 1 -> 4 -> 3, 1 -> 3 -> 4 is the only correct answer, i.e nodes should be grouped sequentially. Hence, 3 -> 1 -> 4 is the wrong answer as we have to preserve the same order.

You are given a string ‘str’, your task is to convert all the characters of the string into lowercase letters.

For example:

You are given, ‘str’ = ‘AbcdEfgh’, in this string if you convert all the characters into lowercase, the string will be ‘abcdefgg’. Hence it is the answer.

Given a string ‘STR’ consisting of lower case English letters, the task is to find the first non-repeating character in the string and return it. If it doesn’t exist, return ‘#’.

For example:

For the input string 'abcab', the first non-repeating character is ‘c’. As depicted the character ‘a’ repeats at index 3 and character ‘b’ repeats at index 4. Hence we return the character ‘c’ present at index 2.

You are given a number 'N'. Your task is to find Nth prime number.

A prime number is a number greater than 1 that is not a product of two smaller natural numbers. Prime numbers have only two factors – 1 and the number itself.

Any number greater than 0 is a natural number i.e. natural numbers N = {1, 2, 3, 4,....}

For example:-

If you are asked to find the 7th prime number, it’ll be 17 because the first 7 prime numbers are 2, 3, 5, 7, 11, 13, 17.

Note: 1 is not a prime number.

Follow Up:

Try to solve the problem in O(N log log N) + O(N).