20 Best Amazon Leetcode Interview Tips with Practice Questions and Answers

Are you planning or preparing for a leetcode interview at Amazon? If yes, then this post is for you.

Its aim is to provide tips and practice questions and answers to boost your chances of a successful interview.

The place of adequate preparation cannot be overemphasized as it concerns passing the Amazon leetcode interview.

Please, read on:

20 Best Amazon Leetcode Interview Tips

Below are helpful tips you can use to boost your performance at Amazon’s leetcode interview:

1.            Don’t look at solutions before putting much effort.

In solving problems, avoid going through the solution before actually spending time in solving it yourself.

2.            Write readable code.

Use significant variable names and make your code modular in the best way possible. This would help a lot during problem solving, data structures and algorithms round.

3.            Be conversant with your projects.

If you’ve done projects (self-projects/jobs) before, then you should be able to explain everything about them, including experiences such as: Most Challenging situations, biggest learning opportunities, most Interesting things, hardest Bugs, most enjoyed parts, conflicts with teammates, etc.

4.            Create and use a good resume format.

Constantly update your resume based on your performance in competitive programming, addition of new projects/internships, open-source contribution, etc.

5.            Learn to code in any preferred language with a strong focus on foundations.

Aim to get so comfortable in coding that if the high-level solution is required of, you should be able to code it without much difficulty.

6.            Be conversant with data structures and Algorithms (DSA).

The most common data structures that you should know are Array, Stack, linked list, Queue, etc.

7.            Learn Object-Oriented Programming (OOP).

Learn the common features of OOP (Abstraction, Inheritance, Polymorphism, and encapsulation).

8.            Learn problem-solving, data structures, and algorithms problems.

Emphasize on solving problems related to data structures, problem-solving, and algorithms.

9.            Learn good coding practices.

Go through design principles to make your code follow standard coding practices.

10.          Acquire confidence in problem-solving and data structures (PS/DS).

Focus on most difficult topics. Work on broadening your knowledge of those topics. After that, solve related problems.

11.          Practice a few machine coding problems.

Try to solve each machine coding problem within one and half hours to improve proficiency. You should be extremely proficient in solving machine coding problems within one and half hour with readable code and a satisfactory design.

12.          Refine computer science foundation notes.

Go through the notes that you’ve created for all the computer science subjects.

13.          Code a few problems.

Start with a few problems on whiteboard or paper to get more proficient in coding.

14.          Go through details about your previous projects.

Ensure you’re able to structure situational questions to real stories from previous projects off the top of your head.

15.          Mock interviews.

Have repetitive mock interview sessions to check your preparation.

16.          Practice Competitive programming (CP).

This will help sharpen your problem-solving skills and will help you become a result-oriented programmer.

17.          Carryout a research on Amazon leetcode basic requirements for each level.

Ensure you’re equipped with the basic requirements for the position of a leetcode programmer.

18.          Practice Open Source contribution.

This may help you learn reputable coding practices by working on projects used by a lot of people.

19.          Have strong foundations of other computer science subjects (Database Management Systems, Operating System, Networking, etc.).

Try to understand the concepts instead of just keeping them memorized.

20.          Apply for internships.

This will help improve your knowledge and exposure in coding.

20 Amazon Leetcode Interview Practice Questions and Answers

Here are some of the most common questions you might come across in an Amazon leetcode interview to use in your interview preparation, including sample answers to practice with:

1. What is leetcode?

Leetcode is a website where software engineers practice their coding skills.

2. What is leetcoode used for?

Leetcode is generally to help software engineers to improve their coding skills, expand knowledge, and prepare for interviews.

3. What is permutation?

Permutation is a selection of r things from a set of n things without replacement and in the right order.

4. Provided with preorder and inorder traversing a tree, construct the two fold tree.

Example, we have 2 arrays, PRE and IN.

Preorder traversing shows that PRE[0] is the root node.

Then we can find this PRE[0] in IN, IN[5].

Now we know that IN[5] is root, so we know that IN[0] – IN[4] is on the left, IN[6] to the end is on the right.

Repeating this on subarrays, we can build a tree out of it.

5. Encode an algorithm to arrange serially and cancel a binary tree.

There is no restriction to how the arrangement should work.

Code the tree in pre-order traversal while “X” is used to denote null node and split node with “,”.

String Builder can be used for building the string on the fly.

For deserializing, we use a Queue to store the pre-order traversal and since “X” is null node, it is known precisely how and where to end the building subtrees.

6. A set of strings containing the following characters ‘( )’, ‘{ }’, and ‘[ ]’, show how valid the input string is.

It is valid if:

The same type of brackets closes the brackets.

The bracket is closed in the right order.

7. What is gray code?

Gray code is a twofold numerical system where two successive values differ only in one.

Gray code sequence starts with “0”.

8. In an array of integers nums, sort the array in an ascending order:

defsortArray(self, nums):

Return sorted (nums)

9. Given two binary trees p and q, write a sequence to check if they are the same tree or not.

Two binary trees are said to be the same if the structures are identical and the nodes have exact same value.

Input: p = [1,2,3], q = [1,2,3]

Output: true.

10. Put up an efficient algorithm that searches for values in an m x n matrix.

Public class Solution {

    Public booleansearchMatrix(int[][] matrix, int target) {

        If(matrix == null || matrix.length< 1 || matrix[0].length <1) {

            Return false;

        }

Int col = matrix[0].length-1;

Int row = 0;

        While(col >= 0 && row <= matrix.length-1) {

            If(target == matrix[row][col]) {

                Return true;

            } else if(target < matrix[row][col]) {

                Col–;

            } else if(target > matrix[row][col]) {

                Row++;

            }

        }

        Return false;

    }

}

11. Explain how you would design Amazon.com to accommodate 20 times traffic than today.

On a high level, you have to calculate metric of three different things:

• User using UI
• Number of calls hitting backend
• Number of calls hitting Database.

Create a bottleneck condition in the above cases, every time there is a bottleneck in any of the case, create a new instance.

12. How would you design an Amazon’s warehouse system?

By using the random placement technique of goods, any product could be found anywhere in the warehouse.

13. Explain how you would design Google’s search autocorrect.

Step 1) Add HTML

Step 2) Create a JavaScript Array

Step 3) Add CSS:

The container must have a relative positioning

Step 4) Add JavaScript

Step 5) Initiate the Autocomplete Effect on “myInput.

14. How would you create a TinyURL?

Copy the desired URL, go to TinyURL.com and paste the long URL, and click on the “make TinyURL” button.

Now you can copy and paste the shortened URL where it is needed.

Here are more questions to practice with in preparing for a leetcode interview with Amazon:

15. Tell us about your experience with a difficult customer.

16. Tell us about a time when you couldn’t meet your deadline.

17. Tell us about a period you took a key decision without substantial data.

18. Tell us about a time you faced an obstacle and how you overcame it.

19. Tell us about a time your project was criticized and rejected.

20. How would you help a new employee who is facing technical difficulties?

10 Good Questions you can ask the Interviewer in an Amazon Leetcode Interview

Here are carefully structured questions you can ask your interviewer; this will provide some level of clarity concerning the demand for a leetcode programmer at Amazon:

1. What are the company’s values? What criteria do you look for in employees in order to hire them?
2. What could represent success in this position, and what is the standard of measuring it?
3. Is there anything about my experience or resume that makes you question my credibility for this role?
4. What are specific details about the position’s day-to-day responsibilities?
5. How does this position impact the organization’s success generally?
6. What do you expect I will achieve in this position?
7. How do employee contributions get incorporated into day-to-day tasks?
8. How does management deliver negative feedback to employees?
9. What are the company’s biggest problems? How are they overcoming them?
10. What do you want the company to represent to employees and clients? — Past, present, and future?

Conclusion

For a successful leetcode interview at Amazon, adequate preparation is required.

One should expect a wide range of questions ranging from coding to problem solving, to interpersonal and behavioral questions in a leetcode interview at Amazon.

We hope that the tips and practice questions and answers shared on this post will be helpful to you in your interview preparation journey, for a successful leetcode interview at Amazon.