SDE - Intern

You have been given an integer array/list(ARR) of size 'N'. It only contains 0s, 1s and 2s. Write a solution to sort this array/list.

Note :

Try to solve the problem in 'Single Scan'. ' Single Scan' refers to iterating over the array/list just once or to put it in other words, you will be visiting each element in the array/list just once.

Ninjas has been given an array. He wants to find a subarray such that the sum of all elements in the subarray is maximum.

Subarray 'A' is greater than sub-array 'B' if sum(A) > sum(B). If two sub-array have the same maximum sum, then output the subarray that has a larger length.

A subarray means a contiguous part of an array. For example, In 'arr' = [1, 2, 3, 4], [1, 2], [2, 3, 4] are the contiguous subarry but [1, 3, 4] is not a subarray.

Note:

More than one sub-array can have a maximum sum, in that case, output any.

You are given an integer 'N'. For a given 'N' x 'N' chessboard, find a way to place 'N' queens such that no queen can attack any other queen on the chessboard.

A queen can be killed when it lies in the same row, or same column, or the same diagonal of any of the other queens. You have to print all such configurations.

Given a singly linked list of integers. Your task is to return the head of the reversed linked list.

For example:

The given linked list is 1 -> 2 -> 3 -> 4-> NULL. Then the reverse linked list is 4 -> 3 -> 2 -> 1 -> NULL and the head of the reversed linked list will be 4.

Follow Up :

Can you solve this problem in O(N) time and O(1) space complexity?