What Is The For
The for-in loop is a fundamental part of iterating through data structures. You should be able to describe its syntax to interviewers without hesitation.
This is the case for-in loop implementation in JavaScript. You would loop through an array by replacing the object name with the array name, and then place the piece of iterative code inside the block.
Generating Combinations And Permutations In Sets Of K
The above two code examples are used for generating pairs of combinations and permutations from a set. That is, each combination or permutation consists of 2 selected elements from the list. If we want to select 3, 4, 5, or K elements for each combination or permutation, a different algorithm is required.
For the case of using a variable length set size, the code will be required to keep track of the last index used, as well as the current index across the set. You can refer to the code examples to find example functions for doing this.
Below is an example of the code running.
19 |
combinationsn// , , , , , , , , , ]combinationsn// , , , , , , , , , ]combinationsn// , , , , ] |
Starting Continuous Learning Activities
Concept Learning/Revision
We need to learn concepts in the proper order of dependencies. If possible, preparing a self note and writing down ideas in a visual format would help a lot in fast revision.
We also advise planning a brainstorming session around each topic with a peer or colleague. If any DSA concepts are challenging to understand, mark them, revisit them later or take help from a mentor. Continuously iterating and never giving up is a basic idea for mastering DSA concepts.
Top 20 Data Structure and Algorithms concepts to master
Problem-solving research
Finding various patterns via coding problems is one of the best approaches to master the problem-solving skill in DSA. The critical questions are: what are the important problem-solving ideas to learn? What would be the best approach to solve a coding problem? Before starting problem-solving, we recommend doing an in-depth analysis of each problem-solving approach via 3-4 coding problems related to it.
Top 20 algorithms to learn Problem-solving
Top 10 problem-solving approaches to master in algorithms
Problem-solving on Paper and Coding Practice
To master problem-solving, paper or a whiteboard can be a handy tool to practice visualizations, solution steps, and pseudo-codes. Writing down algorithm steps and necessary details can help us in designing efficient solutions.
Note: For coding practice, we recommend leetcode. One can find several coding problems organized according to the different difficulty levels.
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Write A Regular Expression That Confirms An Email Id Using The Python Reg Expression Module Re
When it comes to Python algorithms, a lot of the work is usually abstracted by the built-in default data structures or easy methods that can be called in one line. Regular expression algorithms, used for filtering through selections of text, are often some of the most difficult to grasp. Youll have to get familiar with regular expression rules in Python to be able to write out the answer.
What Sort Of Data Structure Allows You To Easily Manipulate Elements In A Connected List
Your answer will show the interviewer you understand multiple forms of data structures. It will also demonstrate your ability to problem solve, prioritize and make quick decisions.
Example:The best data structure to use if you want to move the elements of a connected list around is the linked-list structure. You just change the list rather than creating the array.
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What Is A Stack
A stack is an abstract data type that specifies a linear data structure, as in a real physical stack or piles where you can only take the top item off the stack in order to remove things. Thus, insertion and deletion of items take place only at one end called top of the stack, with a particular order: LIFO or FILO .
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Tips For Smart Learning
- Our goal must be to cover at least 80% syllabus and prioritize the topics based on strengths and weaknesses. A topic that requires more time should get more time.
- Doing a weekly critical review could help us to understand the progress. We need to think what is the further scope of improvement in the topic? What is the current level of our problem-solving ability? For the fact-based view, we recommend rating each topic on a scale of 1 to 10.
- Few ideas always come during learning DSA: Brute force solution, efficient solution, boundary conditions, time and space complexity analysis, coding style. Keep preparing notes if you find something unique or essential patterns.
- In the starting journey, rather than solving many problems, focus on the top 100 coding interview questions. The best idea would be to pick famous coding interview problems which can be solved using various techniques.
- Learn to visualize critical operations, implementations, and use cases of each data structure.
- Never mind going through the same concepts and problems again and again. This would help in figuring out hidden ideas. Focus on reason and never try to memorize!
A blog to explore: Step by step learning plan for interview success
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Weeks 4 & 5 Practice Simple Data Structure And Algorithmic Challenges
As you are familiarizing yourself with data structures, start practicing relatively simple coding problems associated with these data structures and algorithms.
These questions are typically not asked in interviews at big tech companies. Even if they are, theyre usually used as fizz-buzz type warm-up problems. Such questions are also common during phone interviews. However, practicing these coding interview questions will help you internalize the data structures and help you tackle the harder questions which youll be practicing a few weeks from now.
Brush up your array skills with questions like:
- Remove Even Integers from Array
- Merge Two Sorted Arrays
- First Non-Repeating Integer in an Array
- Find Second Maximum Value in an Array
Brush up your Linked List concepts with questions like:
- Find Length of Linked List
- Search in Singly Linked List
- Reverse a Linked List
- Find Middle Value of Linked List
Brush up your Stack/Queue skills with questions like:
- Sort values in Stack
- Create Stack where min returns minimum value in O
- Implement Two Stacks using one Array
Practice Tree Problems like:
- Find minimum value in Binary Search Tree
- Find Height of Binary Tree
- Find kth maximum value in Binary Search Tree
Practice Graph Problems:
- Total number of words in Trie
- Find all words stored in Trie
Practice basic Heap problems:
- Find k smallest elements in a list
- Find k largest elements in an array
Weeks 9 & 10 System Design Interviews
System design interviews are now an integral part of the software engineering interview process particularly if you are applying for a senior role. These interviews have a significant impact on your hiring level.
Learn distributed systems concepts like Cap Theorem, Consistency, Partitioning, Load-Balancing etc.
Look at the course Grokking the System Design Interview for more design interview practice.
As part of your System Design Interviews, you are asked to design a web-scale service. Interviewers are interested in evaluating your ability to describe the different parts of a scale-able service, such as:
- How are web-servers load-balanced?
- How are large files stored?
- How is the network set up for redundancy and maximum throughput?
Youll want to practice questions like:
- Design Instagram
Check out my article the Top 10 System Design Interview Questions for Software Engineers for more example questions, tips, and resources for the System Design Interview.
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What Are The Advantages Of The Heap Over A Stack
In this data structure interview questions, try giving various advantages, along with examples, if possible. It will show the interviewer your domain expertise. Generally, both heap and stack are part of memory and used in Java for different needs:
- Heap is more flexible than the stack because memory space can be dynamically allocated and de-allocated as needed
- Heap memory is used to store objects in Java, whereas stack memory is used to store local variables and function call
- Objects created in the heap are visible to all threads, whereas variables stored in stacks are only visible to the owner as private memory
- When using recursion, the size of heap memory is more whereas it quickly fill-ups stack memory
Post Graduate Program In Data Science
Week 0 What Programming Language Should You Use
Pick a programming language and then stick with it. Im often asked: what if I know more than one? Would, for example, Python be better than Java?
The answer, of course, is that the best programming language for your coding interviews is the language that youre most comfortable with. Most companies/interviewers dont care as long as you can show proficiency in any one mainstream programming language.
In some of the worst cases, Ive seen people deciding to switch to a different programming language in the middle of the interview. Thats a big turn-off and a waste of time. Dont do that. Pick one early, and stick to it throughout.
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What Is An Asymptotic Analysis Of An Algorithm
Asymptotic analysis is the technique of determining an algorithm’s running time in mathematical units to determine the program’s limits, also known as “run-time performance.” The purpose is to identify the best case, worst case, and average-case times for completing a particular activity. While not a deep learning training technique, Asymptotic analysis is an essential diagnostic tool for programmers to analyze an algorithm’s efficiency rather than its correctness.
What Are The Applications Of Graph Data Structures
Graphs can be used in many different scenarios. That includes:
- In map applications, where the intersection of two roads is designated as a node
- Social media applications conceptualize networks of users by assigning each user as a node and their friends as the nodes that they are connected to.
- The Internet can be visualized in terms of a graph, where each page that links to another page has an edge that connects to it in the graph.
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Binary Search And O Time
Companies like to introduce binary search indirectly. You are usually given some input and are told that its sorted. By understanding its sorted, you can then implement a version of binary search based on the context of the problem to find items in O time.
Binary search requires sorted data. Since the data is ordered, when you search through it, you know which direction the item youre looking for must be in. For example with a standard array of sorted integers, if you pick the middle item and compare its value to the target youre looking for, you know its either to the left or right of this middle item and can move in that direction. This eliminates half of the items.
Important Data Structures Visualized With Animations
Coding interviews are an important part of various software engineering, machine learning, and data science jobs. Most of the candidates are good at using programming for their daily-life research problems. But when it comes to a coding interview one needs to brush up on the basics of different data structures since most of the problems revolve around selecting the right data structure for the given problem.
This article will go through seven essential data structures important for a coding interview, their time complexities, and commonly asked coding questions.
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Using List Comprehension Print The Odd Numbers Between 0 And 100
List comprehensions are a feature in Python that allows us to work with algorithms within the default list data structure in Python. Here, were looking for odd numbers.
A list comprehension allows us to simplify our range and filtering algorithm so we can pack it into one line of code. This piece of code returns every element between 0 and 100 if it is divisible by 2.
You should be prepared to describe the list comprehension in detail and with the right notation.
Traversing A Binary Tree: Postorder Traversal
Similar to preorder traversal of a binary tree, postorder traversal is essentially the preorder algorithm, but reversed. In postorder traversal, we hold off from returning the value of the current node, and instead traverse first. We still traverse towards the left, locating the smallest values first, followed by backing up and moving to the right. However, the main difference from preorder traversal is in the order that we return the node values.
The postorder traversal algorithm is shown below.
The code example below shows a postorder traversal of a binary tree.
1 |
20 |
Traversing Iteratively
So far, weve shown code examples for recursively traversing binary trees. This is the simplest way to traverse this type of tree. However, it can also be done iteratively. To traverse iteratively, well be required to keep track of visited nodes that were not yet displaying the values for. We can use a stack for this purpose, popping the next node off of the stack when we reach a leftmost leaf. In this manner, we can traverse, save off nodes, and display node values in the designated pre/post/in order traversal.
The code example below shows inorder traversal of a binary tree, using an iterative style.
1 |
} |
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Now Youre Ready For The Coding Interview
These are some of the best courses to prepare for programming interviews. They will teach you data structure and algorithms that help you to do really well in your interview.
I have also shared a lot of programming interview questions on my blog, so if you are really interested, you can always go there and search for them.
These common coding, data structure, and algorithm questions are the ones you need to know to successfully interview with any company, big or small, for any level of programming job.
If you are looking for a programming or software development job in 2018, you can start your preparation with this list of algorithms and job interview courses.
A good knowledge of data structure and algorithms is important for success in coding interviews and thats where you should focus most of your attention.
Other Programming Interview Resources you may like:From 0 to 1: Data Structures & Algorithms in Java
Closing Notes
Thanks, You made it to the end of the article Good luck with your programming interview! Its certainly not going to be easy, but by following these courses, you are one step ahead than other candidates.
If you like this article, then please share with your friends and colleagues, and dont forget to follow javinpaul on Twitter!
P.S. If you like books then you can also check out my list of top 10 books to prepare for coding interviews.
How Can You Use Linked Lists And Arrays Give Examples
A linked list is a linear data structure where data values are not stored in contiguous memory locations. Image viewer applications can use linked lists to let users go from one image to the next in chronological order. These images dont need to be stored in contiguous locations, but each one needs to point to the next so that users can scroll through the album.
Arrays are simple data structures which store the same types of data values in contiguous locations. Imagine you want to run every day and store your daily distance in a data structure. In that case, you could use an array to store the distance for each day and access previous entries easily.
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Google Data Structure Interview Questions On Arrays
Arrays are a crucial topic that features in coding interviews at Google and other FAANG+ companies. Letâs look at some sample data structures and algorithms interview questions on Arrays.
Take a look at the best Data Structures and Algorithms Courses to crack FAANG interviews.
Ace Your Next Technical Interview
If youâre looking for guidance and help with your Python data structure interview prep, As pioneers in the field of technical interview prep, we have trained thousands of software engineers to crack the most challenging coding interviews and land jobs at their dream companies, such as Google, Facebook, Apple, Netflix, Amazon, and more!
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