Amazon SDE Intern Interview Experience

My code was cleaner than my explanation. That was the biggest lesson from my Amazon SDE Intern interview.

Reading other candidates' experiences helped me a lot while preparing, so here's mine.

Quick Facts

• Role: SDE Intern
• Format: Virtual technical round
• Result: Shortlisted
• Contents: Intro, Coding problems, then leadership principle related questions

Question 1: Spiral (zigzag) level-order traversal of a binary tree

Print the nodes of a binary tree level by level, alternating direction: left to right, then right to left, and so on. For a full tree with nodes 1 to 7, the output is 1 3 2 4 5 6 7.

Approach: A level-by-level BFS, using either two stacks (flipping the order children are pushed on alternate levels) or a queue with every second level reversed.

Complexity: Time O(n), space O(n).

Question 2

Minimum delivery partners on a grid. Given an m × n grid of '1' (house) and '0' (empty), houses connected to each other can be served by one partner. Find the minimum number of partners needed.

Approach: Connected components with DFS. Each time I find an unvisited house, I increment the count and mark everything connected to it as visited.

Complexity: Time O(m × n), space O(m × n) worst case for the stack.

Leadership Principles / behavioral questions

The round ended with questions about decisions I'd made and how I handled difficult situations. The key is being specific about what you personally did, as opposed to what the team did.

What I learned

Solving a problem and communicating a solution are two different skills, and hundreds of LeetCode problems don't teach the second one.

Knowing the optimal approach isn't enough. You have to explain why it works, discuss trade‑offs, and make your thinking easy to follow.