SDE - 1

You are given a Singly Linked List of integers. You need to reverse the Linked List by changing the links between nodes.

We notice that for a perfect square (like 9), the number of factors are always odd, for example:
Number of factors of (16) = # [1,2,4,8,16] = 5
Note that for non-square numbers, factors are even.

As a factor toggles the state of a bulb, bulb number 9 will be toggled by 1,3 & 9. Thus bulb number 9 will switch ON, OFF, ON respectively. Note that odd number of factors cause bulb 9 to be ON at the end.

We note that for odd number of factors is the cause of bulb staying on at the end. Similarly every squared digit bulb will be switched on, and rest will remain off after all factors toggle. Thus the bulbs 1,4,9....81,100 are ON, at the end. Hence 10 bulbs are on.

You have been given a Binary Tree of integers. You are supposed to return the level order traversal of the given tree.

Mutex uses a locking mechanism i.e. if a process wants to use a resource then it locks the resource, uses it and then release it. But on the other hand, semaphore uses a signaling mechanism where wait() and signal() methods are used to show if a process is releasing a resource or taking a resource.
A mutex is an object but semaphore is an integer variable.
In semaphore, we have wait() and signal() functions. But in mutex, there is no such function.
A mutex object allows multiple process threads to access a single shared resource but only one at a time. On the other hand, semaphore allows multiple process threads to access the finite instance of the resource until available.
In mutex, the lock can be acquired and released by the same process at a time. But the value of the semaphore variable can be modified by any process that needs some resource but only one process can change the value at a time.