Program Associate

You have been given a number of stairs. Initially, you are at the 0th stair, and you need to reach the Nth stair.

Each time, you can climb either one step or two steps.

You are supposed to return the number of distinct ways you can climb from the 0th step to the Nth step.

Note:

Note: Since the number of ways can be very large, return the answer modulo 1000000007.

Example :

N=3

We can climb one step at a time i.e. {(0, 1) ,(1, 2),(2,3)} or we can climb the first two-step and then one step i.e. {(0,2),(1, 3)} or we can climb first one step and then two step i.e. {(0,1), (1,3)}.

You are given an array 'ARR' of Integers having 'N' elements. The array contains an encoded message. For each index 'i', 'ARR[i]' denotes the frequency of the 'i'th' character in the message. The characters are of an alien language having 'N' alphabets. Given the frequency of each of the 'N' alphabets in the message, your task is to find out the Huffman codes for each of the 'N' alphabets in the message.

The Huffman Code for a message is the set of codes such that :

1) All codes are binary strings.
2) Each code should be able to determine its corresponding character uniquely.
3) The total numbers of bits used to represent the message are minimized.

Note:

If there are multiple sets of valid Huffman codes for a message. You can print any of them.

For example:

Consider the array ARR = [ 1, 4, 2 ] having 3 elements. 
The array containing Huffman Codes for the above array will be [ '10', '0', '11' ]. Other Valid Huffman Codes are [ '01', '1', '00' ], [ '00', '1', '01' ] etc. Codes like [ '1', '0', '01' ], [ '1', '10' , '0' ] are some of the invalid Huffman Codes.

Ques: What is thread in OS?
Ans: Thread is a path of execution that is composed of a program counter, thread id, stack, and set of registers within the process. It is a basic unit of CPU utilization that makes communication more effective and efficient, enables utilization of multiprocessor architectures to a greater scale and greater efficiency, and reduces the time required in context switching. It simply provides a way to improve and increase the performance of applications through parallelism. Threads are sometimes called lightweight processes because they have their own stack but can access shared data.

Multiple threads running in a process share: Address space, Heap, Static data, Code segments, File descriptors, Global variables, Child processes, Pending alarms, Signals, and signal handlers.

Each thread has its own: Program counter, Registers, Stack, and State.