Qcon Interview Questions and Answers

Use the tilt method to pour exact half water from one container to other without measurements.

• Fill both containers with water

• Tilt one container slowly until water reaches the halfway mark

• Stop pouring when the water level reaches halfway in the other container

The dog will take 28 days to reach the ground.

• The dog climbs 1 foot (3 feet climb - 2 feet drop) each day.

• It needs to climb 30 feet to reach the ground.

• So, it will take 30 days to climb 30 feet, but it will already be on the ground on the 28th day.

Swap adjacent elements, reverse and insert in a linked list.

• To swap adjacent elements, we need to traverse the linked list and swap the nodes.

• To reverse a linked list, we need to traverse the list and change the pointers of each node to point to the previous node.

• To insert a node in a linked list, we need to find the position where we want to insert the node and change the pointers of the nodes accordingly.

Different types of joins in SQL include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN.

• INNER JOIN: Returns rows when there is at least one match in both tables.

• LEFT JOIN: Returns all rows from the left table and the matched rows from the right table.

• RIGHT JOIN: Returns all rows from the right table and the matched rows from the left table.

• FULL JOIN: Returns rows when there is a match in one of the tables.

Shared pointers are a type of smart pointer used in C++ to manage memory allocation.

• Shared pointers allow multiple pointers to refer to the same object, automatically managing the object's lifetime.

• They use reference counting to keep track of how many pointers are pointing to the object.

• When the last shared pointer goes out of scope, the object is automatically deleted.

• They help prevent memory leaks and dangling pointers.

• Example: std::shared_ptr ptr1 = std::make_shared();

• Exam...read more

Overloading is using the same method name with different parameters. Overriding is creating a new implementation of a method in a subclass.

• Overloading allows multiple methods with the same name but different parameters.

• Overriding allows a subclass to provide its own implementation of a method from its superclass.

• Overloading is resolved at compile-time while overriding is resolved at runtime.

• Examples of overloading: print(int), print(float), print(string)

• Examples of overriding...read more