Software Engineer

You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to return the list of all pairs of elements such that each sum of elements of each pair equals 'S'.

Note:

Each pair should be sorted i.e the first value should be less than or equals to the second value. 

Return the list of pairs sorted in non-decreasing order of their first value. In case if two pairs have the same first value, the pair with a smaller second value should come first.

Given the count of total stones in a game. Two-player ‘Ale’ and ‘Bob’ are playing the game. Your task is to find who will win the game if both the players are playing optimally.

Rules of the game.

1. In a single turn, a player can choose a single stone or ‘even’ number of stones.

2. They will play alternatively, which means in the first chance ‘Ale’ will collect the stones, in second-chance ‘Bob’ will collect the stones. And always ‘Ale’ will start the game.

3. If any player is not able to take any stones then another player will win the game.

Given an unsorted array of integers, you have to move the array elements in a way such that all the zeroes are transferred to the end, and all the non-zero elements are moved to the front. The non-zero elements must be ordered in their order of appearance.

For example, if the input array is: [0, 1, -2, 3, 4, 0, 5, -27, 9, 0], then the output array must be:

[1, -2, 3, 4, 5, -27, 9, 0, 0, 0].

Expected Complexity: Try doing it in O(n) time complexity and O(1) space complexity. Here, ‘n’ is the size of the array.

You have been given a Binary Tree of 'N' nodes where the nodes have integer values.

Your task is to find the largest number that could be formed by concatenating all its nodes values.

For example:

For the given binary tree:   

Output: 96553210    

Explanation: After concatenating all the numbers in the above binary tree this is the largest number that can be formed.