Worldline 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.