Amazon DSA Interviews are not just a test on the fundamentals of software engineering concepts. It evaluates candidates on real-time scenarios like how to handle complex user requests, failure and downtime, and the scaling of the architecture. Candidates are gauged on problem solving skills and logic based solutions.
Amazon’s systems operate at millions of requests per sec
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We will discuss the top 20 Amazon DSA interview questions from rece
Key Takeaway
- Amazon DSA in
terviews are designed to assess algorithmic efficie ncy, data s tructure selection, and the ability to reason clearly under real-world engin ee ring constraints, not just coding correctness. - Strong
performance requires ma stery of core DSA patterns across arrays, trees, graphs, heaps, and dynamic programming, with prep aration focused on recognizing patterns and making optimal trade-offs rath er than memorizing solutions. - Candidates are expected to thin
k aloud, clarify problem assumptions b efore coding, justify design decision s, an d demonstrate engineering judgment that aligns with Amazon’s leadership principles throughout the problem-solving process.
What is DSA?
Data Structures an
In the context of an Amazon interview, DSA is not just abo
Profi
20 Frequently Asked Amazon D
Amazon interviews consistently focus on a
Each pr
Working through these questions wi
The patterns you identify here will repeat acros
1. Partition Labels
You a
Then, iterate through t
Some Other Questions
- Sp
lit string into maximum numbe r of unique substrings focuses on greedy partitionin g while ensuring every substr ing remains unique across the string. - Maximum number of non-overlapping substrings evaluates interval expansion and optimal boundary selection.
- Divide string into groups of consecu
tive ch aracters tests accurate detection of contiguous character segments. - P
artition string into substrings wi th equal frequency combines f requ ency tracking with valid partition logic. - Split a string in balanced strings v
alidates greedy counting usin g balanc e condition s.
2. Reorganize String
Given a string s, you must rearrange the characters so that any two adj
The optimal strategy is to c
Some Other Questions
- Rearrange string k distance apart tests frequency-based reordering with distance constraints using a heap.
- Sort characters by fre
quency evaluates priority queue usage for dynamic frequency ranking. - Longest happy string tests greedy characte
r selection u nder repetition constraints. - Remove adjacent duplicates applies stack-based logic to enforce adjacency rules.
- Ta
sk scheduler evaluates freq uency management with cooldown constr aints.
3. Search Suggestion System
As
Some Other Questions
- Implement trie validates construction and traversal of prefix-based data structures
. - Design autocomplete sy
stem combines trie logic with ranking and frequency updates. - Replace words app
lies prefix matching to optimize word replace ment using a dictionary. - Longest comm
on prefix tests prefix comparison across mul tiple strings. - Word search ii combines trie traversal with dfs o
n a gr id.
4. Trapping
Fo
The most efficient approach uses t
Some Other Questions
- Container with most water tests two-pointer optimization for maximizin
g area. - Pour water simul
ates w ater f low with boundary c onstraints. - Trapping rain water ii extends water trapping to a two-dimensional grid using a heap.
- Largest rectangle in histo
gram tests monotoni c stack mastery. - Maximal rectangle applies histogram logic within a matrix.
5. Ma
You are assigned to put boxes on a truck. You are given a 2D array boxTypes and an inte
The solution is to sort the box types by the number of units per box in descending order, then greedily pick boxes wi
Some Other Questions
- Assign cookies tests greedy matchin
g to maximize satisfaction. - Bag of tokens evaluates decision-making under resource trade-
offs. - Minimum cost to connect
sti cks m inimizes total cost thr ough gre edy merging. - Minimum number of arrows to burs
t balloons solves interval overlap efficiently.
6. LRU Cache (Least Recently Used)
You are asked to design a data structure that foll
The hash map stores the key -> No
Some Other Questions
- LFU cache
extends cache design with frequency tracking. - Design browser history tests bidirectional traversal and state management
. - Design h
ashmap validates fun dame ntal data structure implement ation. - Design circular deque focuses on pointer control and
edge cases. - Design twitter combine
s multiple data structures into a scalable system.
A linked list is given such that ea
Ideally, you interweave the cop
Some Other Questions
Clone graph applies deep copy logic to cyclic graph structur e s. - Flatten multilevel doubly linked
list tests po inter restru cturing a cross levels. - Deep co
py of graph reinforces safe duplicati on using visited trac king. - Linked list cycle ii detects and locates cycles efficiently.
- Remove zero sum consecutive nodes uses prefix sums to m
odify linked lists.
8. Two Sum / Pairs of Songs With Total Durat
These ar
The optimal approach is to ite
Some Other Questions
- Three sum extends pair logic
using sorting and two pointers. - Four sum tests p
runing strategies and duplicate ha ndling. - Subarray sum equals k applies prefix sum hashing.
- Co
unt nice pairs in an array combines mathematical transformation with hashing. - Pairs with given difference evaluates complement-based lookup logic.
9. Number of Islands
Given an m x n
To solve it, iterate through the grid; whenever you s
Some Other Questions
- Max area of island extends traversal to compute connected component size.
- Closed islands tests boundary-aware gri
d traversal. - Island perimeter combines traversal with perimeter ca
lculation. - Making a large island merges components to max
imize area. - Surrounded regions isolates regions not connected to borders.
10. Rotting Oranges (or Z
In a grid where 0 is empty, 1 is a fresh orange, and 2 is rotten, every minute a rotten orange rots adjacent fresh oranges. You must return the minimum time until no fresh orange remains. It is a classic multi-source BFS problem.
Unlike simple BFS, th
Some Other Questions
- Walls and
ga te s computes m inimum distance using bfs. - Shortest path in binary matrix finds optimal paths in a grid wi
th obstacles. - As far from land as possible applies multi-sourc
e bfs for distance maximizat ion. - Zombi
e in a matrix s imula tes time-based spread across a grid. - Shortest distance from al
l buildings aggregate s distances using bfs.
11. Critical Connections i
Given a network of serve
Perform a DFS and re
Some Other Questions
- Find bridges in the graph that identify edges critical to c
onnectivity. - Articulation points in a graph detects nodes whose removal disconnects the graph.
- Redundant connection ii identi
fies unnecessa ry edges in directed graphs. - Networ
k delay time comp utes signal propagation delays. - Disconnect isla
nd tests minimal operations to break connecti vity.
12. Course Schedule
T
You can use Kahn’s
Some Other Questions
- Alien d
ic tionary derive s char acter order from pa rtia l c onstraints. - S
equ e nce reconstruction validates uniqueness of topological ordering. - Minimum height trees fin
ds optimal roots using graph trimming. - Find eventual safe s
tates identifies terminal nodes in directed graphs. - Parallel courses introduces level-based scheduling constraints.
13. Word Ladder
You must transform a beginWord to an endWord by changing one letter at a time using a given dictionary, finding the s
You sho
Some Other Questions
- Word ladder II reconstructs all shortest transformation paths.
- Minimum genetic mutation applies bfs on constrained state transitions.
- Open the lock explores a finite state space
usi ng bfs. - String transformation
models transformations as a graph problem . - Shortes
t t ransformation s equence computes minimum steps require d.
14. Boundary of Binar
Ret
The solution involves splitting the problem into t
Some Other Questions
- Bina
ry tree right side view captures visible nodes using level traversal. - Level order traversal performs breadth-first traversal on trees.
- Vertical or
der trav ersa l organizes nodes by column inde x. - Zigzag l
evel order traversal alternates traversal direction per level. - D
iameter of binary tree compute s the lo ngest path betwe en nodes.
15. Lowest Common Ancestor (LCA)
Fi
For a binary tree, recursively search left and right; if both return non-null, the current node is the LCA. Time complexity is O(n).
Some Other Questions
- LCA in a binary search tree leverages ordering properties for efficiency.
- LCA of deepest leaves combines depth tracking with ancestor selection.
- Distance between two nodes in a tr
ee computes distance using LCA. - Smallest subtree with all deepest nodes
finds minimal covering subtree. - Kth ancestor of a tree node applies binary lifting.
16. K Closest Points to O
Given an array of points (x,y), find the K closest points to the origin (0,0). This sorting p
Some Other Questions
- Top K frequent elements selects elements based on frequency.
- Kth largest element in an array applies selection a
lgorit hms. - Find K pairs with smallest sums uses a heap over pair co
mbinations. - Find K closest elements a
pplies binary sea rch on window s ize. - Kth smallest elem
ent in a sorte d ma trix searches value space efficiently.
17. Merge K Sorted L
You need to merge k linked lists that are already sorted. It t
Some Other Questions
- Merge two sorted lists applies basic merging logic.
- Merge sorted array performs in-place merging.
- Sort list applies merge sort on lin
ked lists. - Flatten a linked list merges multi-level sorte
d lists. - Smallest range covering elements from K lists tracks
overlapping ranges.
18. Longest Palindromic Substring
Find the longest palindrome within a string. It tests dynamic pro
Some Other Questions
- Palindromic substrin
gs count s al l palindromic s egments. - Valid palindrome II allows a single deletion.
- Shortest palindrome builds the shortest palindrome by prefix addition.
- Longest palindrome constructs the maximum-length palindrome fro
m ch aracter s. - Count different palindromic subsequences tracks unique palindromes using DP.
A
Some Other Questions
- Return to origin tracks position updates thro
ugh instructions. - Judge circle determines circul
ar movement based on final orientation. - Robot simulation executes move
ment with obstacle handling. Spira l matrix appl ies directional traversal logic. - Execute r
obot i nstructions simulates state transitions.
20. Median of Two Sorted Arrays
Find the median of two sorted arrays of size m a
Some Other Questions
- Kth smallest el
ement in two sorte d arrays uses partition-based selection. - Median from d
ata stream maintains balance usi ng two heaps. - Kth largest eleme
nt applies selection techniques. - Split array largest sum per
forms binary search on feasible answers. - Search in rotated sor
ted array ap plies modified binary search logic.
What Interviewers Expect From a Candidate in Amazon DSA Interviews?
Amazon int
- Problem Decomposition and Clarity: Interviewers exp
ect you to restate the problem clearly, identify constraints, and break it down into logical steps before writing code. This shows structured thinking and r educes ambigu ity. - A
lgorithmic Trade-offs Awareness: You should be able to compare brute-force and optimized approache s, explain time and space complexity, and justify why a particular data structure or algorithm is the best fit for the given constraints. - Communication Whi
le Coding: Amazon values candidates who think out loud, explain decisions as they code, and ke ep the int erviewer aligned with their reasoning rather than coding in silence. - Edge-Case a
nd Failure Handling: Interviewers look for produ ction-minded thinking, in cluding handling null inpu ts, large data set s, duplicates, and boundary conditions. - Code Quali
ty and Maintainability: Clean variable naming, logical s tr ucture, and readable code signal that you can write soft war e meant to survive beyond the interview.
Pre
Stro
The “Bar Raiser”
In ev
Furthermore, think out loud. A
Leadership Principles (LPs) in Code
You might think LPs are only for behavioral questions,
Demonstrate bias for act
Simulati
Do not memorize the code, memorize the pattern. If you see “to
Mock Interviews
Amazon typically uses Amazon Chime and a collaborative code e
Common Mistakes to Avoid in Amazon DSA Interv
Strong problem-solving skills alone are not enough to clear A
- Coding in Silen
ce: A major mistake is reading the problem and silently writing code fo r 15 minutes. Instead, treat the interviewer as a coworker. Say, “I’m thinking of using a hash map here to store frequencies. Does that sound reasonable?” This keeps them engaged and allows them to ste er you away from dead ends. - Ignoring Space Complexity: Cand
idates often optimize time complexity to O(n) but use O(n) space when a n O(1 ) space solution exis ted. Amazo n cares deeply about hardware costs. Always ask, “Can we do this in-place?” or mention the trade-off: “I am trading memory for speed here.” - Sloppy Variable Naming: Using variables like i, j, k, dp, or te
mp is a mistake. Use descriptive names like currWindowStart, maxProfit, or visitedNodes. It shows you “insist on highest s tandards.”
Not Dry Running the Code- Writing the code and immediately saying “I’m done” is dan gerous. You must manually walk through your code with a sample input before the interview er asks you to. Say, “Let me trace this with the input [1, 2, 3] to check for off-by-on e errors.”
Overlooking Edge Cases: Assuming the input is always perfect i s a fatal error. Always wri te test cases for empty input, negative numbers, extremely large numbers (integer overflow), and duplicates.
Crack DSA interview Question With Confidence
Amazon’s online assessment filters DSA fundamentals through DSA interview questions. Coding rounds evaluate algorithmic efficiency
System design interviews assess scalability and trade-offs. Behavioral rounds judge decisions through Amazon’s leader
Aspiring candidates can now crack the DSA interview with ease with Interview Kickstart’s FAANG DSA coding masterclass. Understand core data structures and algorithms needed to solve interval-based problems. Learn how to frame your solutions and communicate trade-offs in high-bar interviews. By end of the masterclass you’ll gain confidence to crack DSA interview.
Conclusion
The Amazon DSA interview questi
With structured prac
FAQs: Amazon DSA Interview Questions
Q1. Which programming language should I use for Amaz
Us
Q2. How much time do I get to solve a question?
A typical round lasts 60 minutes
Q3. Do I need to implement the solution perfectly witho
While syntax errors are often forgiven, logical bugs a
Q4. Is Dynam
Yes, but usually at the standard patt
Q5. What if I don’t know the answer to a question?
Don’t panic. State that you have not seen this specific problem but explain how you would tr
