22 questions · from 5 interviews · 3 asked more than once
Arista interview questions
Every question candidates reported from their Arista interviews, most frequently asked first. Each links to the write-up it came from, so you can see the round and how it went.
Arista coding and DSA questions
- 01
Difference Between Binary Tree and Binary Search Tree
Explain the differences between a binary tree and a binary search tree.
Easy · Asked 2 times · From Arista Software engineer interview| Off campus
- 02
Kth Smallest Element in a BST
Given a Binary Search Tree (BST), find the kth smallest element.
Medium · Asked 2 times · From Arista Software engineer interview| Off campus
- 03
LFU Cache
Implement an LFU (Least Frequently Used) cache with get(key) and put(key, value) operations. When the cache reaches its capacity, the key with the lowest access frequency should be evicted. If multiple keys share the same frequency, evict the least recently…
Hard · From Arista OA Experience 2026 | Aptitude + Core CS + 3 Coding Questions
- 04
API Bandwidth Allocation
Given a maximum available bandwidth, a list of API endpoints each with a required bandwidth (weight) and a number of requests it can resolve (value), allocate bandwidth to maximize the total number of resolved requests without exceeding the bandwidth limit.…
From Arista OA Experience 2026 | Aptitude + Core CS + 3 Coding Questions
- 05
Split Circular Linked List into Two Alternating Halves (Inplace)
Given a circular linked list (e.g., 1-2-3-4-5-6), split it inplace into two normal linked lists containing alternating nodes (e.g., list 1: 1-3-5, list 2: 2-4-6). The solution must be inplace, without creating new lists, and require writing the full code.
- 06
Split Circular Linked List into Two Normal Lists (In-place)
Given a circular linked list (e.g., 1-2-3-4-5-6), split it into two normal linked lists (e.g., 1-3-5 and 2-4-6). The operation must be performed in-place without creating new lists, and the full code had to be written.
- 07
Implement Custom Array.prototype.reduce
I was tasked with implementing my own version of the Array.prototype.reduce function, named customReduce , which should replicate its standard behavior.
- 08
Find Number of Zero-Sum Segments
Find number of segments whose sum is zero.
Medium · From Arista SDE 2 Interview Experience
- 09
Find Number of Segments with Any Given Sum
Modify the program so that it will work for any sum.
Medium · From Arista SDE 2 Interview Experience
Arista system design questions
- 01
Design an E-commerce System
Interviewer asked to design an e-commerce system. Need to do it on white board. The interview involved in-depth discussions across multiple areas.
Hard · From Arista SDE 2 Interview Experience
Arista other questions
- 01
Explain Segmentation Fault
Explain what a segmentation fault is, why it happens, and when it typically occurs.
Asked 2 times · From Arista Software engineer interview| Off campus
- 02
fork() Output Question
Code snippet: cpp int main() { fork(); printf("Hello"); fork(); printf("Hello"); fork(); printf("Hello"); } Determine how many times the string "Hello" is printed. The execution creates 2 prints after the first fork, 4 after the second, and 8 after the third,…
Easy · From Arista OA Experience 2026 | Aptitude + Core CS + 3 Coding Questions
- 03
FIFO Page Replacement
Given 4 frames and the reference string 1 2 3 4 5 1 3 1 2, compute the number of page faults using the FIFO replacement policy. The trace results in page faults for the accesses: 1,2,3,4,5,1,2 (7 faults total).
Easy · From Arista OA Experience 2026 | Aptitude + Core CS + 3 Coding Questions
- 04
Hashing – Number of Collisions
Hash table size is 10. Keys: 43, 165, 62, 123, 142. Using h(x) = x % 10, the hash values are 3,5,2,3,2 respectively, causing collisions at values 3 and 2. Total collisions: 2.
Easy · From Arista OA Experience 2026 | Aptitude + Core CS + 3 Coding Questions
- 05
Bitwise XOR
Compute D = A ^ B where A = 01000001 and B = 01000010. Performing bitwise XOR yields D = 00000011.
Easy · From Arista OA Experience 2026 | Aptitude + Core CS + 3 Coding Questions
- 06
Time Complexity of Nested Loops
Analyze the time complexity of: cpp for (int i = 1; i <= n; i++) { for (int j = 1; j <= n; j += i) { for (int k = 1; k <= n; k += 2) { // O(1) } } } The inner k loop runs O(n) times, the j loop runs approximately n/i times, and the outer i loop runs n times.…
Medium · From Arista OA Experience 2026 | Aptitude + Core CS + 3 Coding Questions
- 07
C Debugging: Pointers, Structs, Type Casting
A debugging question in C involving pointers, struct data types, and type casting (forcing string to int then again to char).
- 08
C Debugging: Pointers, Structs, Type Conversion
A debugging question in C involving pointers, struct data types, and type conversions (string to int, then int to char).
- 09
JavaScript 'this' Context Output
I was asked to determine the output of the following JavaScript code snippets, specifically how the this keyword behaves in both a regular function call and a strict mode function call: function test1() { console.log(this); } test1(); "use strict"; function…
- 10
Invoking Function with Specific Context and Arguments
The interviewer presented a scenario with a function and an object, and asked how to invoke the function such that its this context refers to the provided object, while also passing specific arguments: function introduce(city, country) {…
- 11
Calling Function from Object via Prototype
I was given a Person constructor and a standalone sayHello function. The challenge was to enable calling sayHello as a method of an object created by Person , such as p1.sayHello() , given the following initial code: function Person(name) { this.name = name;…
- 12
Java Pass by Value/Reference with Primitive, Array, and Object
Question was where we have three different methods, one with int parameter, next with int[] parameter, lastly with an object of a class. All three methods were changing the values of the parameter. Need to figure out what will be the impact on those objects.…
Easy · From Arista SDE 2 Interview Experience
Arista interview questions FAQ
What questions are asked in Arista interviews?
Candidates reported 22 distinct questions across 5 Arista interviews. 9 coding and DSA questions, 1 system design questions, 12 other questions.
Which Arista interview questions are asked most often?
The most repeated are "Explain Segmentation Fault" (2 times), "Difference Between Binary Tree and Binary Search Tree" (2 times), "Kth Smallest Element in a BST" (2 times).
How difficult are Arista interview questions?
Of the questions candidates rated, 50% were easy, 33% medium and 17% hard.