Software Engineer

You are given a Singly Linked List of integers and a positive integer 'K'. Modify the linked list by reversing every alternate 'K' nodes of the linked list.

A singly linked list is a type of linked list that is unidirectional, that is, it can be traversed in only one direction from head to the last node (tail).

Note:

If the number of nodes in the list or in the last group is less than 'K', just reverse the remaining nodes. 

Example:

Linked list: 5 6 7 8 9 10 11 12
K: 3 

Output: 7 6 5 8 9 10 12 11

We reverse the first 'K' (3) nodes and then skip the next 'K'(3) nodes. Now, since the number of nodes remaining in the list (2) is less than 'K', we just reverse the remaining nodes (11 and 12). 

Note:

You need to reverse the first 'K' nodes and then skip the 'K' nodes and so on. 5 6 7 10 9 8 11 12 is not the correct answer for the given linked list. 

You are given a positive integer ‘N’. Your task is to find the total number of ‘1’ in the binary representation of all the numbers from 1 to N.

Since the count of ‘1’ can be huge, you are required to return it modulo 1e9+7.

Note:

Do not print anything, just return the number of set bits in the binary representation of all integers between 1 and ‘N’.

You are given a string ‘S’. You are also given ‘M’ integers in an array ‘A’. You perform ‘M’ operations on this string. The operations are given in an array ‘A’ of size ‘M’.

You perform the operations in the order they appear in the array ‘A’. In the ‘i’th operation, you reverse the substring of ‘S’ from the position ‘A[i]’ to ‘len(S)’ - ‘A[i]’ - 1 (0 based).

Your task is to find the string after performing all the operations.

Example :

‘S’ = “aabcd”, ‘M’ = 2, ‘A’ = [0, 1]
After 1st operation i.e, reversing from [0, 4], ‘S’ = “dcbaa”.
After 2nd operation i.e, reversing from [1, 3], ‘S’ = “dabca”.
Hence, the answer is “dabca”.

Semaphores ?
Mutex ?
Multithreading ?
Paging vs Swapping ?

Where are you from? Who is in your family and what they do ? Why you took MCA ?