Please follow the below guidelines for answering questions.

1. Answer within the question bank itself, without changing the name.

2. Color your answers with blue color. 

3. Color your execution results in yellow color. Sometimes you might be asked to first answer without trying out and then actually try compiling/executing it. This step is not mandatory.

Problem:

Find the middle element of linked list in one Pass.

Approach:

You can use the runner technique.  

Two pointers can be used and both will be running at separate speeds. One runner pointer can go in two steps at a time and other pointer can go in one step at a time. Second one will always cover half the distance as that of the other. When one reaches the end, other will be be middle.

Write a program that accept two directories (or even two drives or hard disks), efficiently compare them and tell the files/locations which are not same. It should also tell if a file has been changed based on factors such as size, timestamp etc.

Basically it needs to act as a file system backup tool that suggests the files that need to updated to the backup device or vice versa. However, it may not actually copy the files or do the backup.

Important Points

This is a quick summary of important keywords and reserved words that you should not be using as an identifier. Identifier is a name given to any class, method, interface, enum or variable that we create. There is also added quick notes section with few important keywords that may be useful for exam or interview preparations.

Keywords in Java

• class, interface, enum(added in 5.0), package, import, new, this,  super, return, void.

Based on the scope in which the variable is declared, we can classify variables as Class variables, Instance Variables and Local variables.

Class variables (or static variables)

Class variables (or static variables) uses the static keyword. Class variables (or static variables) are declared within a class and outside all methods

Example: Static variable

class MyClass{