Amazon Interview Experience SDE 1 (DSA-focused)
Summary
I completed three interview rounds focusing on DSA and system thinking, and identified the core patterns needed to succeed.
Full Experience
Had 3 rounds — here are the key problems asked:
Round 1:
- Longest island → perimeter + coordinates (DFS/BFS)
- Minimum arrows to burst balloons (Greedy - intervals)
Round 2:
- Convert BST → height-balanced BST (Inorder + recursion)
- First missing positive (Array indexing / cyclic sort)
Round 3:
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No direct DSA
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Focus shifted to system thinking + deep dive on past projects
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Data structures:
- Monthly sales → HashMap
- Top-K items → Heap / Priority Queue
Key Takeaways:
- Strong grip on core patterns is enough (DFS, Greedy, Heap, Arrays, Trees)
- Optimization + edge cases matter
- Be ready to explain your approach clearly
Prep used: Striver Sheet + LeetCode 75/150
If you're preparing for Amazon, these patterns cover most of the ground.
Interview Questions (4)
Longest Island
Find the longest island in a grid using DFS/BFS to compute its perimeter and coordinates.
Minimum Number of Arrows to Burst Balloons
Given intervals representing balloons, determine the minimum number of arrows needed to burst all balloons using a greedy interval approach.
Convert BST to Height-Balanced BST
Convert a given binary search tree into a height-balanced BST using inorder traversal and recursion.
First Missing Positive
Find the first missing positive integer in an unsorted array using array indexing / cyclic sort.
Preparation Tips
Prep used: Striver Sheet + LeetCode 75/150