Amazon Coding Interview 2025: Top 50 Questions Every Candidate Must Know

The Amazon Coding Interview 2025 is one of the most challenging yet rewarding tests in the tech industry. Amazon, being one of the largest and most innovative tech companies in the world, demands only the best. As a candidate, it’s essential to be well-prepared and have a deep understanding of data structures, algorithms, and problem-solving techniques. In this article, we will cover the top 50 questions every candidate must know to ace the Amazon Coding Interview in 2025. By practicing these questions, you can boost your chances of success and showcase your technical skills.

Understanding the Amazon Coding Interview Process

Before diving into the questions, it’s important to understand the Amazon Coding Interview Questions 2025 process. Typically, the interview consists of several rounds:

1. Online Assessment (OA): This is the first step and generally includes multiple-choice questions (MCQs) and coding challenges. You are required to solve these problems within a specific time frame.

2. Technical Interview (Phone/Video): In this round, you will be asked to solve coding problems in real-time while discussing your approach with the interviewer.

3. On-site Interview: This involves a series of interviews with different team members. Expect questions related to algorithms, problem-solving, system design, and behavioral aspects.

It’s important to note that Amazon uses a competency-based approach, so focus on demonstrating your problem-solving abilities, coding skills, and understanding of computer science fundamentals.

Key Areas to Focus On for the Amazon Coding Interview

Amazon is particularly focused on the following areas during coding interviews:

• Data Structures: Arrays, Linked Lists, Stacks, Queues, Hash Maps, Trees (especially Binary Trees and Binary Search Trees), Heaps, Graphs.

• Algorithms: Sorting, Searching, Dynamic Programming, Divide and Conquer, Backtracking.

• System Design: Although this is generally for senior positions, Amazon often assesses candidates for scalable, robust, and efficient system design.

• Problem-solving and Optimization: Solving problems in the most efficient way with an emphasis on time and space complexity.

• Behavioral Questions: Amazon places a strong emphasis on its leadership principles, so be prepared to answer questions related to team collaboration, challenges, and leadership.

Now that we know what to expect, let’s dive into the Amazon Coding Interview Questions 2025.

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Top 50 Amazon Coding Interview Questions 2025

1. Reverse a Linked List

   • Problem: Write a function to reverse a singly linked list.

   • Concept: Linked List, Pointers, Recursion.

2. Find the Missing Number in an Array

   • Problem: Given an array of n-1 numbers, find the missing number from 1 to n.

   • Concept: Array, Mathematical Formula, XOR.

3. Two Sum

   • Problem: Given an array of integers, return the indices of the two numbers such that they add up to a specific target.

   • Concept: HashMap, Array.

4. Longest Substring Without Repeating Characters

   • Problem: Given a string, find the length of the longest substring without repeating characters.

   • Concept: Sliding Window, HashMap.

5. Reverse a String

   • Problem: Reverse a string in place.

   • Concept: String, Pointers, Two-Pointer Technique.

6. Merge Intervals

   • Problem: Given a collection of intervals, merge all overlapping intervals.

   • Concept: Sorting, Greedy Algorithm.

7. Find the Middle of a Linked List

   • Problem: Find the middle element of a linked list in a single pass.

   • Concept: Linked List, Fast and Slow Pointer.

8. Balanced Parentheses

   • Problem: Given a string of parentheses, determine if it is balanced.

   • Concept: Stack, String.

9. Detect a Cycle in a Linked List

   • Problem: Determine if a linked list has a cycle.

   • Concept: Floyd’s Cycle Detection Algorithm, Fast and Slow Pointer.

10. Find Kth Largest Element in an Array

• Problem: Find the kth largest element in an unsorted array.

• Concept: Heap, Sorting, Quickselect.

11. Find the Duplicate Number

• Problem: Given an array of n integers where each integer is between 1 and n-1, find the duplicate number.

• Concept: Tortoise and Hare Algorithm, Floyd’s Cycle Detection.

12. String to Integer (Atoi)

• Problem: Implement the atoi function, which converts a string to an integer.

• Concept: String Manipulation.

13. Power of Two

• Problem: Check if a number is a power of two.

• Concept: Bit Manipulation.

14. Top K Frequent Elements

• Problem: Given a non-empty array of integers, return the k most frequent elements.

• Concept: HashMap, Sorting.

15. Valid Palindrome

• Problem: Determine if a string is a palindrome, considering only alphanumeric characters.

• Concept: String, Two-pointer Technique.

16. Anagram Check

• Problem: Check if two strings are anagrams of each other.

• Concept: HashMap, Sorting.

17. Find All Substrings

• Problem: Given a string, find all substrings of it.

• Concept: String, Iteration.

18. Find the Maximum Product of Two Integers

• Problem: Given an array of integers, find the maximum product of any two integers.

• Concept: Sorting, Two Pointers.

19. Find the Diameter of a Binary Tree

• Problem: Given a binary tree, find the diameter (longest path between two nodes).

• Concept: Binary Tree, DFS.

20. Find All Pairs in an Array that Sum Up to a Given Target

• Problem: Find all pairs in the array whose sum is equal to a target value.

• Concept: HashMap, Sorting.

21. Subarray Sum Equals K

• Problem: Given an array of integers and a target sum k, find the total number of continuous subarrays that sum to k.

• Concept: Prefix Sum, HashMap.

22. Kth Smallest Element in a Binary Search Tree

• Problem: Given a binary search tree, find the kth smallest element.

• Concept: Binary Search Tree, Inorder Traversal.

23. Search in Rotated Sorted Array

• Problem: Search a sorted array that has been rotated.

• Concept: Binary Search.

24. Climbing Stairs

• Problem: Given a staircase with n steps, how many ways can you climb to the top?

• Concept: Dynamic Programming.

25. Word Break Problem

• Problem: Given a string and a dictionary of words, check if the string can be segmented into space-separated words.

• Concept: Dynamic Programming, Backtracking.

26. Find Peak Element

• Problem: Find a peak element in an array where an element is greater than its neighbors.

• Concept: Binary Search.

27. Coin Change Problem

• Problem: Given a set of coins and a total value, find the minimum number of coins needed.

• Concept: Dynamic Programming.

28. Maximal Rectangle

• Problem: Find the area of the largest rectangle in a histogram.

• Concept: Stack, Array.

29. Word Ladder

• Problem: Given two words and a dictionary, find the shortest transformation sequence from start to end.

• Concept: BFS, Graph.

30. Median of Two Sorted Arrays

• Problem: Find the median of two sorted arrays.

• Concept: Binary Search, Merge.

31. Find Missing Number in Arithmetic Progression

• Problem: Given an arithmetic progression, find the missing number.

• Concept: Arithmetic Progression, Math.

32. Implement Trie (Prefix Tree)

• Problem: Implement a trie with insert and search functions.

• Concept: Trie, String.

33. Sudoku Solver

• Problem: Write a function to solve a Sudoku puzzle.

• Concept: Backtracking.

34. Find Majority Element

• Problem: Find the majority element in an array (appears more than n/2 times).

• Concept: HashMap, Boyer-Moore Voting Algorithm.

35. Sliding Window Maximum

• Problem: Given an array and a window size, find the maximum value in each window.

• Concept: Deque, Sliding Window.

36. Longest Common Subsequence

• Problem: Find the longest common subsequence of two strings.

• Concept: Dynamic Programming.

37. Longest Increasing Subsequence

• Problem: Find the longest increasing subsequence in an array.

• Concept: Dynamic Programming.

38. Edit Distance

• Problem: Given two strings, find the minimum number of operations required to convert one string into another.

• Concept: Dynamic Programming.

39. Matrix Rotation

• Problem: Rotate a matrix by 90 degrees.

• Concept: Matrix, In-place Rotation.

40. Find the Intersection of Two Arrays

• Problem: Find the common elements between two arrays.

• Concept: HashSet, Sorting.

41. Max Subarray Sum

• Problem: Find the maximum sum of a contiguous subarray.

• Concept: Kadane’s Algorithm.

42. Partition Equal Subset Sum

• Problem: Determine if an array can be partitioned into two subsets with equal sum.

• Concept: Dynamic Programming.

43. Palindrome Partitioning

• Problem: Find all possible palindrome partitions of a string.

• Concept: Backtracking, String.

44. Course Schedule

• Problem: Given a number of courses and their prerequisites, determine if it’s possible to finish all the courses.

• Concept: Graph, Topological Sorting.

45. N-Queens Problem

• Problem: Solve the N-Queens problem using backtracking.

• Concept: Backtracking, Recursion.

46. Count and Say

• Problem: Generate the nth term of the "Count and Say" sequence.

• Concept: String Manipulation.

47. LCA (Lowest Common Ancestor) of a Binary Tree

• Problem: Find the lowest common ancestor of two nodes in a binary tree.

• Concept: Binary Tree, LCA.

48. Find the Smallest Subarray with a Sum Greater than a Given Value

• Problem: Find the smallest subarray with a sum greater than a given target.

• Concept: Sliding Window.

49. Subsets

• Problem: Given a set of distinct integers, return all possible subsets.

• Concept: Backtracking.

50. Find the Minimum Path Sum in a Grid

• Problem: Given a grid filled with non-negative numbers, find a path from the top-left to the bottom-right corner that minimizes the sum of the numbers along the path.

• Concept: Dynamic Programming, Grid.

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Conclusion

Preparing for the Amazon Coding Interview Questions 2025 is crucial for securing a job at this tech giant. By practicing these 50 questions and understanding the concepts behind them, you will be well-equipped to handle a variety of coding challenges. Remember, consistent practice is key to mastering the skills required for this rigorous interview process. Good luck!