Amazon Software Engineer Interview Questions and Answers for Freshers

Find the element that is repeated once in an array where all elements are repeated twice

• Iterate through the array and use a hashmap to keep track of the count of each element

• Once the iteration is complete, check the hashmap for the element with a count of 1

Count the number of distinct islands in a 2D grid of '1's (land) and '0's (water).

• Use Depth-First Search (DFS) or Breadth-First Search (BFS) to explore each island.

• Mark visited land cells to avoid counting them multiple times.

• Iterate through the grid; for each unvisited '1', initiate a search and increment the island count.

• Example: In a grid like [[1,1,0],[0,0,1],[1,0,1]], there are 3 islands.

Detect if a binary tree is symmetric.

• Check if the left and right subtrees are mirror images of each other.

• Use a recursive approach to compare corresponding nodes.

• Base case: if both nodes are null, return true.

• If one node is null and the other is not, return false.

• If the values of the nodes are not equal, return false.

• Recursively check if the left subtree of the left node is symmetric to the right subtree of the ri...read more

Finding the merge point of two linked lists.

• Traverse both linked lists to find their lengths.

• Move the pointer of the longer list ahead by the difference in lengths.

• Iterate both lists simultaneously until the merge point is found.

Given an infinite staircase with a broken kth step, find the maximum height we can reach in n rounds of jumping i steps.

• We can start by jumping the maximum number of steps in each round until we reach the broken step.

• After reaching the broken step, we can discard the i steps that would land us on the broken step and jump the remaining steps.

• We can continue this pattern until we reach the maximum height we can reac...read more

The question is about advanced data structures and algorithms for a senior software engineer role.

• Focus on advanced data structures like AVL trees, B-trees, and tries

• Discuss complex algorithms like Dijkstra's algorithm, A* search algorithm, and dynamic programming

• Highlight experience with optimizing time and space complexity

• Provide examples of solving challenging coding problems or implementing complex algorithms