SDE - Intern

Implement a Stack Data Structure specifically to store integer data using two Queues.

There should be two data members, both being Queues to store the data internally. You may use the inbuilt Queue.

Implement the following public functions :

1. Constructor:
It initializes the data members(queues) as required.

2. push(data) :
This function should take one argument of type integer. It pushes the element into the stack and returns nothing.

3. pop() :
It pops the element from the top of the stack and, in turn, returns the element being popped or deleted. In case the stack is empty, it returns -1.

4. top :
It returns the element being kept at the top of the stack. In case the stack is empty, it returns -1.

5. size() :
It returns the size of the stack at any given instance of time.

6. isEmpty() :
It returns a boolean value indicating whether the stack is empty or not.

Operations Performed on the Stack:

Query-1(Denoted by an integer 1): Pushes an integer data to the stack. (push function)

Query-2(Denoted by an integer 2): Pops the data kept at the top of the stack and returns it to the caller. (pop function)

Query-3(Denoted by an integer 3): Fetches and returns the data being kept at the top of the stack but doesn't remove it, unlike the pop function. (top function)

Query-4(Denoted by an integer 4): Returns the current size of the stack. (size function)

Query-5(Denoted by an integer 5): Returns a boolean value denoting whether the stack is empty or not. (isEmpty function)

Example

Operations: 
1 5
1 10
2
3
4

Enqueue operation 1 5: We insert 5 at the back of the queue.
  Queue: [5]

Enqueue operation 1 10: We insert 10 at the back of the queue.
  Queue: [5, 10]

Dequeue operation 2: We remove the element from the front of the queue, which is 5, and print it.
  Output: 5
  Queue: [10]

Peek operation 3: We return the element present at the front of the queue, which is 10, without removing it.
  Output: 10
  Queue: [10]

IsEmpty operation 4: We check if the queue is empty.
  Output: False
  Queue: [10]

You are given a string (STR) of length N, consisting of only the lower case English alphabet.

Your task is to remove all the duplicate occurrences of characters in the string.

For Example:

If the given string is:
abcadeecfb

Then after deleting all duplicate occurrences, the string looks like this:
abcdef

You are given a singly Linked List of integers. Your task is to return true if the given singly linked list is a palindrome otherwise returns false.

For example:

The given linked list is 1 -> 2 -> 3 -> 2-> 1-> NULL.

It is a palindrome linked list because the given linked list has the same order of elements when traversed forwards and backward​.

Follow Up:

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

You are given a two-dimensional grid having 'N' rows and 'M' columns, consisting of upper case characters. You are also given a word 'WORD'. You have to find the number of occurrences of that word in the grid.

Starting from a given cell, a word can be formed by moving in all eight directions: horizontally left, horizontally right, vertically up, vertically down, and four diagonal directions.

Example :

There are three occurrences of the word 'NINJA' in the following grid:

Note :

1) Given word will not be a single character.

2) If occurrences of the given word start from two different cells, then these two occurrences are considered to be different.

Consider the word 'XYX' to be searched in the string 'AXYXB'. Here, we find an occurrence of 'XYX' at index 2 going in the right direction, and another occurrence at index 4 going in the left direction.

Although these two words correspond to the same word, they will be considered as different occurrences.

Given a sequence of numbers ‘ARR’. Your task is to return a sorted sequence of ‘ARR’ in non-descending order with help of the merge sort algorithm.

Example :

Merge Sort Algorithm -

Merge sort is a Divide and Conquer based Algorithm. It divides the input array into two-parts, until the size of the input array is not ‘1’. In the return part, it will merge two sorted arrays a return a whole merged sorted array.

The above illustrates shows how merge sort works.

Note :

It is compulsory to use the ‘Merge Sort’ algorithm.

Explain Normalization Techniques. (Learn)
Explain Transactions.
 

What is LRU?
What is Memory Management?