Strings
A string is an ordered sequence, or string, of characters. It is usually considered a data type and is often included as part of language primitives. In most languages, strings are implemented using an array of bytes. The bytes are encoded using some character encoding. Earlier systems used ASCII encoding, with Unicode encoding used in later systems. Learn more.
Trees
A tree is an abstract hierarchical data structure. It is represented by a group of linked nodes, with a single root node. Each node can have zero or multiple children. A leaf is a node with no children. Learn more.
1 Easy graph questions
For plenty more graph questions, see 50+ graph interview questions.
How to prepare for a coding interview
If youre reading this article, it probably means that youre already up and running on the most important step towards preparing to ace a coding interview at Facebook, Google, Amazon, Microsoft, LinkedIn, Airbnb or another tech company: practicing a lot of questions.
However, thats not all you need to be confident of killing it in an interview situation. To make sure youre really, truly prepared, we recommend following the three steps below. For extra tips, take a look at our list of 21 coding tips from ex-interviewers.
Trade Off – Organize Fixed Size Arrays
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Stacks and queues
Stacks and queues are similar and complementary in many ways. Both are a sequenced collection of elements that are generally accessed one element at time, and they are implemented using similar data structures. Learn more.
Graphs
A graph is an abstract data structure represented by vertices connected by edges. Vertices are also known as nodes. Vertices sharing an edge are known as adjacent. Learn more.
1 Easy array questions
How did you get on? To practice with more array questions like this, check out our list of 50+ array questions with solutions.
1 Easy tree questions
Check out plenty more tree questions here: 50+ tree questions and solutions.
1 Easy map questions
You can find lots more map questions to practice with right here: 50+ map interview questions.
Arrays
Arrays are one of the most fundamental data structures in programming and computer science, and many more complex data structures are built using arrays. Learn more.
The ultimate data structure cheat sheet
When youre preparing for coding interviews, it helps to have at least some of the key information in one place. Weve created an 8-page cheat sheet, which you can use as a handy reference point for the 8 main data structures.
Just put your email in the form below, and well send it straight to you (dont worry, we wont bombard you with endless emails).
Right, lets take a look at some typical data structure questions.
Maps
A map is a data structure that allows us to access a value by key. This is in contrast to an array that allows us to access a value by index. A common kind of map is a hash map (also called a hash table), which stores keys along with associated values (for example, a telephone directory which associates phone numbers with names). Learn more.