Amazon Coding Questions - DSA Problems & Solutions

Company Overview

Amazon’s coding round focuses on data structures and algorithms with a bar for clean code and optimal solutions. The online assessment (OA) typically has 2 coding problems in about 90 minutes; technical interviews extend into DSA, system design (for senior roles), and Leadership Principles. Difficulty ranges from medium to hard, with emphasis on graphs, sliding window, dynamic programming, and bit manipulation. Practicing LeetCode-style problems and explaining your approach clearly will help.

Amazon Coding Round at a Glance

OA: 2 coding problems, ~90 minutes total. Languages: Java, C++, Python. Technical interviews: 1–2 DSA problems per round, sometimes system design. Focus: Optimal time/space complexity, edge cases, and clear communication.

Amazon Coding Questions Overview

Amazon OA Coding Section:

• Problems: 2 coding problems
• Time: 90 minutes total
• Languages: Java, C++, Python

Coding Problems

Question 1: Two Sum

Q1: Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

Solution (Java):

public int[] twoSum(int[] nums, int target) {
    Map<Integer, Integer> map = new HashMap<>();
    for (int i = 0; i < nums.length; i++) {
        int complement = target - nums[i];
        if (map.containsKey(complement)) {
            return new int[]{map.get(complement), i};
        }
        map.put(nums[i], i);
    }
    return new int[]{};
}

Time Complexity: O(n)

Question 2: Longest Substring Without Repeating Characters

Q2: Find the length of the longest substring without repeating characters.

Solution (Java):

public int lengthOfLongestSubstring(String s) {
    Map<Character, Integer> map = new HashMap<>();
    int maxLen = 0;
    int left = 0;

    for (int right = 0; right < s.length(); right++) {
        char c = s.charAt(right);
        if (map.containsKey(c) && map.get(c) >= left) {
            left = map.get(c) + 1;
        }
        map.put(c, right);
        maxLen = Math.max(maxLen, right - left + 1);
    }

    return maxLen;
}

Time Complexity: O(n)

Company-Specific Focus Areas

Amazon frequently tests graphs (BFS/DFS, shortest path, topological sort), sliding window and two pointers, dynamic programming (1D and 2D), bit manipulation, and hash maps/sets. Strong emphasis on time and space complexity and handling edge cases. Leadership Principles often tie into how you approach problems and communicate.

Related Resources

Amazon 2024 Papers

Previous year papers with coding questions

View 2024 Papers →

Amazon Technical Questions

Technical questions with solutions

View Technical Questions →

Amazon Main Page

Complete Amazon placement guide

View Main Page →

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Practice Amazon coding questions regularly. Focus on DSA fundamentals, optimal solutions, and clear communication—aligned with Amazon’s bar.

Last updated: February 2026