OneBanc Technologies Backend Developer Interview Questions and Answers

To find a loop in a linked list, we use Floyd's cycle-finding algorithm.

• Floyd's cycle-finding algorithm uses two pointers, one moving at a rate of one node per iteration and the other moving at a rate of two nodes per iteration.

• If there is a loop in the linked list, the two pointers will eventually meet at some node.

• To find the starting point of the loop, we reset one of the pointers to the head of the linked list and ...read more

Minimum cost to reach last cell of 2D matrix with only downward or right moves.

• Use dynamic programming approach to solve the problem.

• Calculate minimum cost for each cell by considering minimum cost of its adjacent cells.

• Final answer will be the minimum cost to reach the last cell.

Design a stack that supports getMin functionality to return the minimum element in the stack.

• Create two stacks, one for storing the actual elements and another for storing the minimum elements.

• Push elements onto both stacks simultaneously.

• When popping an element, pop from both stacks.

• To get the minimum element, peek at the top of the minimum stack.

TreeSet is a data structure that stores unique elements in sorted order.

• TreeSet is implemented using a Red-Black tree

• It provides O(log n) time complexity for basic operations like add, remove, and contains

• It also provides methods like first(), last(), headSet(), tailSet(), and subSet()

• TreeSet can be used to implement priority queues and sorting algorithms

Design an ArrayList with getMax functionality.

• Create a custom ArrayList class that extends the existing ArrayList class.

• Add a getMax() method that returns the maximum value in the list.

• Override the add() method to keep track of the maximum value in the list.

• Update the maximum value whenever an element is added or removed from the list.

Dagger is required for dependency injection in Android development.

• Dagger helps in managing dependencies and reduces boilerplate code.

• It provides compile-time safety and improves code readability.

• Dagger also helps in testing and modularizing the codebase.

• It is widely used in Android development for building scalable and maintainable apps.

The garbage collector in Android automatically manages memory by reclaiming unused objects.

• Garbage collector identifies objects that are no longer referenced by the program.

• It frees up memory occupied by these objects, making it available for future use.

• The process involves marking objects as reachable or unreachable, and then reclaiming memory from unreachable objects.

• Garbage collection can be triggered automatically ...read more

To set equal spacing between childs of constraint layout, use the chain style property.

• Create a chain of the views that need equal spacing using the chain style property.

• Set the chain style to spread inside the constraint layout.

• Adjust the margins of the views to control the spacing.

• Use the layout_constraintHorizontal_chainStyle or layout_constraintVertical_chainStyle attribute to set the chain style.

• Example: app:layou