SRE

You are given a positive integer 'N'. Your task is to find the number of strings of length ‘N’ that can be formed using only the characters ‘a’, ‘b’ and ‘c’. The strings formed should be such that the number of ‘b’ and ‘c’ in the string is at most 1 and 2, respectively.

Example:

Let’s say N = 2. The strings of length 2, which satisfy the given constraints are: “aa”, “ab”, “ac”, “ba”, “bc”, “ca”, “cb”, “cc”. Hence, the output is 8.

You are given a Singly Linked List of integers and an integer array 'B' of size 'N'. Each element in the array 'B' represents a block size. Modify the linked list by reversing the nodes in each block whose sizes are given by the array 'B'.

Note:

1. If you encounter a situation when 'B[i]' is greater than the number of remaining nodes in the list, then simply reverse the remaining nodes as a block and ignore all the block sizes from 'B[i]'. 

2. All block sizes are contiguous i.e. suppose that block 'B[i]' ends at a node cur, then the block 'B[i+1]' starts from the node just after the node cur.

Example

Linked list: 1->2->3->4->5
Array B: 3 3 5

Output: 3->2->1->5->4

We reverse the first block of size 3 and then move to block 2. Now, since the number of nodes remaining in the list (2) is less than the block size (3), we reverse the remaining nodes (4 and 5) as a block and ignore all the block sizes that follow.

You must implement the Stack data structure using a Singly Linked List.

Create a class named 'Stack' which supports the following operations(all in O(1) time):

getSize: Returns an integer. Gets the current size of the stack

isEmpty: Returns a boolean. Gets whether the stack is empty

push: Returns nothing. Accepts an integer. Puts that integer at the top of the stack

pop: Returns nothing. Removes the top element of the stack. It does nothing if the stack is empty.

getTop: Returns an integer. Gets the top element of the stack. Returns -1 if the stack is empty

Given a string, determine if it is a palindrome, considering only alphanumeric characters.

Palindrome

A palindrome is a word, number, phrase, or other sequences of characters which read the same backwards and forwards.

Example:

If the input string happens to be, "malayalam" then as we see that this word can be read the same as forward and backwards, it is said to be a valid palindrome.

The expected output for this example will print, 'true'.

From that being said, you are required to return a boolean value from the function that has been asked to implement.

What is Deadlock?

What is Semaphore?

What is normalisation?

What is Acid Properties?