Interview Questions and Answers

Separate out 0's, 1's, and 2's in an array

• Create three variables to count the number of 0's, 1's, and 2's in the array

• Loop through the array and increment the respective variable for each occurrence

• Create a new array and add the counted number of 0's, 1's, and 2's in order

Design a system for a gaming android app like ludo.

• Implement game logic for ludo including dice rolling, moving pieces, and winning conditions.

• Create a user interface with a game board, player pieces, and dice.

• Incorporate multiplayer functionality for online play.

• Include features like in-game chat, leaderboards, and customizable game settings.

• Utilize a backend server to handle game synchronization and data storage.

Remove duplicates from given array of strings

• Create a new empty array

• Loop through the original array and check if the element already exists in the new array

• If not, add it to the new array

• Return the new array

Loop in linked list can be detected using Floyd's cycle-finding algorithm.

• Floyd's cycle-finding algorithm uses two pointers, one moving at twice the speed of the other.

• If there is a loop, the faster pointer will eventually catch up to the slower pointer.

• If there is no loop, the faster pointer will reach the end of the list.

• Time complexity of this algorithm is O(n) and space complexity is O(1).

Search for a target value in a rotated sorted array using binary search

• Find the pivot point where the array is rotated

• Determine which half of the array the target value lies in

• Perform binary search on the appropriate half of the array

Designing a recommendation system for YouTube

• Utilize collaborative filtering to recommend videos based on user preferences

• Incorporate content-based filtering to suggest videos similar to ones previously watched

• Implement a hybrid approach combining collaborative and content-based filtering for more accurate recommendations

Use synchronization mechanisms like locks or synchronized blocks to ensure only one thread can access the method at a time.

• Use synchronized keyword in method signature

• Use synchronized blocks inside the method

• Use ReentrantLock for more fine-grained control