Designnex Technologies Interview Questions and Answers

Vending machine design patterns involve creating efficient and user-friendly interfaces for purchasing products.

• Consider using the Factory Method pattern to create different types of vending machines.

• Implement the State pattern to manage the different states of the vending machine (e.g. idle, dispensing, out of stock).

• Use the Observer pattern to notify the vending machine when products are restocked or when a purchase is made.

• Apply the Strategy pattern to allow for different ...read more

To find the last k nodes from the end of a linked list, we can use a two-pointer approach.

• Use two pointers, one starting at the head of the linked list and the other starting k nodes ahead.

• Move both pointers simultaneously until the second pointer reaches the end of the linked list.

• The first pointer will now be at the kth node from the end.

The most common element in a string is the character that appears the most frequently.

• Use a hashmap to store the frequency of each character in the string

• Iterate through the string and update the frequency count in the hashmap

• Find the character with the highest frequency in the hashmap

To find the middle of a single linked list, use two pointers - one moving twice as fast as the other.

• Use two pointers - slow and fast

• Move slow pointer by one node and fast pointer by two nodes

• When fast pointer reaches end, slow pointer will be at the middle

Intersection of linked list is finding the common node(s) between two linked lists.

• Traverse both linked lists and store nodes in a set, then check for common nodes

• Use two pointers approach to find the intersection point

• If one list is longer, move the pointer of the longer list to the same distance from the end as the shorter list