SDE - Intern

Given an integer ‘N’ representing the number of pairs of parentheses, Find all the possible combinations of balanced parentheses with the given number of pairs of parentheses.

Note :

Conditions for valid parentheses:
1. All open brackets must be closed by the closing brackets.

2. Open brackets must be closed in the correct order.

For Example :

()()()() is a valid parentheses.
)()()( is not a valid parentheses.

Stack is a data structure that follows the LIFO (Last in First out) principle. Design and implement a stack to implement the following functions:

1. Push(num): Push the given number in the stack if the stack is not full.

2. Pop: Remove and print the top element from the stack if present, else print -1.

3. Top: Print the top element of the stack if present, else print -1.

4. isEmpty: Print 1 if the stack is empty, else print 0.

5. isFull: Print 1 if the stack is full, else print 0.

You have been given ‘m’ operations which you need to perform in the stack. Your task is to implement all the functions of the stack.

Example:

We perform the following operations on an empty stack which has capacity 2:

When operation 1 1 is performed, we insert 1 in the stack.

When operation 1 2  is performed, we insert 2 in the stack. 

When operation 2 is performed, we remove the top element from the stack and print 2.

When operation 3 is performed, we print the top element of the stack, i.e., 3.

When operation 4 is performed, we print 0 because the stack is not empty.

When operation 5 is performed, we print 0 because the stack is size 1, which is not equal to its capacity.

You are given two non-negative numbers 'num1' and 'num2' represented in the form of linked lists.

The digits in the linked lists are stored in reverse order, i.e. starting from least significant digit (LSD) to the most significant digit (MSD), and each of their nodes contains a single digit.

Calculate the sum of the two numbers and return the head of the sum list.

Example :

Input:
'num1' : 1 -> 2 -> 3 -> NULL
'num2' : 4 -> 5 -> 6 -> NULL

Output: 5 -> 7 -> 9 -> NULL

Explanation: 'num1' represents the number 321 and 'num2' represents 654. Their sum is 975.

You are given a linked list containing 'n' 'head' nodes, where every node in the linked list contains two pointers:

(1) ‘next’ which points to the next node in the list

(2) ‘child’ pointer to a linked list where the current node is the head.

Each of these child linked lists is in sorted order and connected by 'child' pointer.

Your task is to flatten this linked such that all nodes appear in a single layer or level in a 'sorted order'.

Input: Given linked list is:

Output:
1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → 9 → 12 → 20 → null.


Explanation:
The returned linked list should be in a sorted order. All the elements in this returned linked list are connected by 'child' pointers and 'next' pointers point to null.

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