Coding interviews are tough. But fortunately, there's a tried and proven method to get better at them. With a combination of studying, practicing questions and doing mock interviews, getting that dream job can become a reality.

* Decide on a programming language
* Study CS fundamentals
* Practice solving algorithm questions
* Internalize the Do's and Don'ts of interviews
* Know what signals and behaviours interviewers are looking out for
* Practice doing mock interviews
* Interview successfully to get the job

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

You may assume that each input would have exactly one solution, and you may not use the same element twice.

You can return the answer in any order.



Example 1:

Input: nums = [2,7,11,15], target = 9
Output: [0,1]
Output: Because nums[0] + nums[1] == 9, we return [0, 1].

Example 2:

Input: nums = [3,2,4], target = 6
Output: [1,2]


Example 3:

Input: nums = [3,3], target = 6
Output: [0,1]


Constraints:

2 <= nums.length <= 103
-109 <= nums[i] <= 109
-109 <= target <= 109

Only one valid answer exists.

Solution will be provided tomorrow.

Simple soution in Java:

public int[] twoSum(int[] nums, int target) {
for (int i = 0; i < nums.length; i++) {
for (int j = i + 1; j < nums.length; j++) {
if (nums[j] == target - nums[i]) {
return new int[] { i, j };
}
}
}
throw new IllegalArgumentException("No two sum solution");
}


Complexity Analysis
Time complexity : O(n^2). For each element, we try to find its complement by looping through the rest of array which takes O(n) time. Therefore, the time complexity is O(n^2).
Space complexity : O(1). 

Python interview questions (part 1):

What's the difference between a tuple and a list?

Both tuples and lists are data structures in Python and hold a list of values. Unlike lists, tuples are immutable - they can't be changed.


What is a dict and what's its most important limitation?

A dict is a structure akin a hash map. It stores key-value pairs, where keys are unique and it has O(1) access time. The most important limitation for a dict is that the keys must be hashable/immutable. Meaning, we can use a tuple as a key, but not a list.


What is pickling/unpickling?

Pickling is converting an object to a string representation in python. Generally used for caching and transferring objects between hosts/processes.

This is a straight-to-the-point, distilled list of technical interview Do's and Don'ts, mainly for algorithmic interviews. Some of these may apply to only phone screens or whiteboard interviews, but most will apply to both.

During coding

✅ Explain what you are coding/typing to the interviewer, what you are trying to achieve.
✅ Practice good coding style. Clear variable names, consistent operator spacing, proper indentation, etc.
✅ Type/write at a reasonable speed.
✅ As much as possible, write actual compilable code, not pseudocode.
✅ Write in a modular fashion. Extract out chunks of repeated code into functions.

❌ Remain quiet the whole time.
❌Spend too much time writing comments.
❌ Use extremely verbose or single-character (unless they're common like i, n) variable names.

Algorithms for coding interview
https://www.programcreek.com/2013/08/leetcode-problem-classification/

This post summarizes the common subjects in coding interviews, including:
1) String/Array/Matrix,
2) Linked List,
3) Tree,
4) Heap,
5) Graph,
6) Sorting,
7) Dynamic Programming,
8) Bit Manipulation,
9) Combinations and Permutations,
10) Math

MySQL Database Interview Questions for Beginners and Intermediates

1. Define SQL?

Answer: SQL stands for Structured Query Language. SQL is a programming Language designed specially for managing data in Relational Database Management System (RDBMS).

2. What is RDBMS? Explain its features?

Answer : A Relational Database Management System (RDBMS) is the most widely used database Management System based on the Relational Database model.

Features of RDBMS
Stores data in tables.
Tables have rows and column.
Creation and Retrieval of Table is allowed through SQL.

3. What is Data Mining?
Answer : Data Mining is a subcategory of Computer Science which aims at extraction of information from set of data and transform it into Human Readable structure, to be used later.

4. What is an ERD?
Answer : ERD stands for Entity Relationship Diagram. Entity Relationship Diagram is the graphical representation of tables, with the relationship between them.

5. What is the difference between Primary Key and Unique Key?
Answer : Both Primary and Unique Key is implemented for Uniqueness of the column. Primary Key creates a clustered index of column where as an Unique creates unclustered index of column. Moreover, Primary Key doesn’t allow NULL value, however Unique Key does allows one NULL value.

Typical HTML Interview Exercises

Markup validation

Consider the following markup.
Is it valid? If not, can you explain why?

#html

Answer

The markup uses the picture element, which is a pretty new addition to the specification. The code is all valid apart from the last image specified in the srcset attribute; 320y isn’t a valid value. If the y is replaced with a w, it becomes valid though.

#html

2. The main element

Can you explain the definition of the main element? What is its goal? Are the two specifications (WHATWG and W3C) in agreement on its definition?

Answer

The main element has two different definitions depending on the specification used.

The W3C specification describes it as the main content of the page, that is, the content that describes the main topic of a page or is the central functionality of an application. The specification also states that a document must not include more than one main element.

#html

3. The small element

Describe when it’s appropriate to use the small element and provide an example.

Answer

In HTML 4.01 the small element was a presentational element to mark up smaller text. In HTML5 it should be used semantically to represent legal disclaimers, caveats, and so on. The text may well be “small”, but this isn’t required.

An example of its use is shown below:

<img src="image.jpg" alt="London by night">
<small>The copyright of this image is owned by Aurelio De Rosa</small>

#html

4. Images and accessibility

Is the alt attribute mandatory on img elements? If not, can you describe a scenario where it can be set to an empty value? Does an empty value affect accessibility in any way?

Answer

The alt attribute is mandatory on img elements but its value can be empty (i.e. alt=""). An empty value is recommended when the image shown is used for decorative purposes only and therefore isn’t part of the content of the page. With regards to accessibility, if the alt attribute is empty, screen readers will ignore the image. This is highly recommended because using a value of something like “Content separator” will only disturb the user when this text is spoken.

#html

5. The time element

Is it possible to express a date range using a single time element?

Answer

No, it isn’t possible. The information can be expressed using two time elements though. For example to describe a time interval ranging from November 6, 2014 to November 9, 2014, a developer can write:

<time datetime="2014-11-06">6</time>-
<time datetime="2014-11-09">9 November 2014</time>

#html

Top JavaScript interview questions.
What's good to hear in answer and what raises red flag:

1. Can you name two programming paradigms important for JavaScript app developers?

JavaScript is a multi-paradigm language, supporting imperative/procedural programming along with OOP (Object-Oriented Programming) and functional programming. JavaScript supports OOP with prototypal inheritance.

Good to hear:

Prototypal inheritance (also: prototypes, OLOO).
Functional programming (also: closures, first class functions, lambdas).

Red flags:

No clue what a paradigm is, no mention of prototypal oo or functional programming.

#javascript #js