Problem database last updated: June 20, 2025
34 problems · 11 Easy, 21 Medium, 2 Hard · Ranked #59 of 458
11 Easy
32% · avg 23%
21 Medium
62% · avg 59%
2 Hard
6% · avg 18%
Based on 34 reported problems, Arista Networks interviews are easier than average - only 6% Hard compared to 18% across all companies. The majority (62%) of questions are Medium difficulty, which is typical for companies that want to see solid fundamentals without excessive trick questions.
Compared to the industry average, Arista Networks puts unusual emphasis on binary-search-tree (5.9% of problems, 5.2x the industry average), linked-list (23.5% of problems, 3.3x the industry average), recursion (14.7% of problems, 3.3x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are array (35.3%), hash-table (26.5%), string (23.5%), linked-list (23.5%). Problems below are sorted by frequency, the ones at the top are asked most often.
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
Construct String With Repeat Limit You are given a string s and an integer repeatLimit. Construct a new string repeatLimitedString using the characters of s such that no letter appears more than... | Medium | Very Likely | hash-tablestringgreedy | Solve |
Restore IP Addresses A valid IP address consists of exactly four integers separated by single dots. Each integer is between 0 and 255 (inclusive) and cannot have leading zeros. | Medium | Very Likely | stringbacktracking | Solve |
Find the Town Judge In a town, there are n people labeled from 1 to n. There is a rumor that one of these people is secretly the town judge. | Easy | Very Likely | arrayhash-tablegraph | Solve |
Reverse Nodes in k-Group Given the head of a linked list, reverse the nodes of the list k at a time, and return the modified list. | Hard | Very Likely | linked-listrecursion | Solve |
Reverse Linked List II Given the head of a singly linked list and two integers left and right where left <= right, reverse the nodes of the list from position left to position right,... | Medium | Very Likely | linked-list | Solve |
Reorder List You are given the head of a singly linked-list. The list can be represented as: | Medium | Very Likely | linked-listtwo-pointersstack | Solve |
Contains Duplicate II Given an integer array nums and an integer k, return true if there are two distinct indices i and j in the array such that nums[i] == nums[j] and abs(i - j) <=... | Easy | Very Likely | arrayhash-tablesliding-window | Solve |
Rotated Digits An integer x is a good if after rotating each digit individually by 180 degrees, we get a valid number that is different from x. Each digit must be rotated - we... | Medium | Very Likely | mathdynamic-programming | Solve |
Remove Linked List Elements Given the head of a linked list and an integer val, remove all the nodes of the linked list that has Node.val == val, and return the new head. | Easy | Likely | linked-listrecursion | Solve |
LRU Cache Design a data structure that follows the constraints of a Least Recently Used (LRU) cache. | Medium | Likely | hash-tablelinked-listdesign | Solve |
Search in Rotated Sorted Array There is an integer array nums sorted in ascending order (with distinct values). | Medium | Likely | arraybinary-search | Solve |
Missing Number Given an array nums containing n distinct numbers in the range [0, n], return the only number in the range that is missing from the array. | Easy | Likely | arrayhash-tablemath | Solve |
Maximum Depth of Binary Tree Given the root of a binary tree, return its maximum depth. | Easy | Likely | treedepth-first-searchbreadth-first-search | Solve |
Merge Two Sorted Lists You are given the heads of two sorted linked lists list1 and list2. | Easy | Likely | linked-listrecursion | Solve |
Course Schedule II There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1. You are given an array prerequisites where prerequisites[i] = [ai, b... | Medium | Likely | depth-first-searchbreadth-first-searchgraph | Solve |
Binary Tree Maximum Path Sum A path in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an edge connecting them. A node can only appear in the sequ... | Hard | Likely | dynamic-programmingtreedepth-first-search | Solve |
Maximum Units on a Truck You are assigned to put some amount of boxes onto one truck. You are given a 2D array boxTypes, where boxTypes[i] = [numberOfBoxesi, numberOfUnitsPerBoxi]: | Easy | Likely | arraygreedysorting | Solve |
Kth Largest Element in a Stream You are part of a university admissions office and need to keep track of the kth highest test score from applicants in real-time. This helps to determine cut-of... | Easy | Likely | treedesignbinary-search-tree | Solve |
Palindromic Substrings Given a string s, return the number of palindromic substrings in it. | Medium | Likely | two-pointersstringdynamic-programming | Solve |
Flatten a Multilevel Doubly Linked List You are given a doubly linked list, which contains nodes that have a next pointer, a previous pointer, and an additional child pointer. This child pointer may o... | Medium | Likely | linked-listdepth-first-searchdoubly-linked-list | Solve |
Search a 2D Matrix You are given an m x n integer matrix matrix with the following two properties: | Medium | Likely | arraybinary-searchmatrix | Solve |
Integer to Roman Seven different symbols represent Roman numerals with the following values: | Medium | Likely | hash-tablemathstring | Solve |
Contains Duplicate Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct. | Easy | Likely | arrayhash-tablesorting | Solve |
Find the Winner of the Circular Game There are n friends that are playing a game. The friends are sitting in a circle and are numbered from 1 to n in clockwise order. More formally, moving clockwis... | Medium | Likely | arraymathrecursion | Solve |
Best Time to Buy and Sell Stock You are given an array prices where prices[i] is the price of a given stock on the ith day. | Easy | Likely | arraydynamic-programming | Solve |
Implement Trie (Prefix Tree) A trie (pronounced as "try") or prefix tree is a tree data structure used to efficiently store and retrieve keys in a dataset of strings. There are various appl... | Medium | Likely | hash-tablestringdesign | Solve |
Path Sum II Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where the sum of the node values in the path equals targetSum. Each path... | Medium | Likely | backtrackingtreedepth-first-search | Solve |
Kth Missing Positive Number Given an array arr of positive integers sorted in a strictly increasing order, and an integer k. | Easy | Likely | arraybinary-search | Solve |
Top K Frequent Elements Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order. | Medium | Likely | arrayhash-tabledivide-and-conquer | Solve |
Remove All Occurrences of a Substring Given two strings s and part, perform the following operation on s until all occurrences of the substring part are removed: | Medium | Likely | stringstacksimulation | Solve |
Merge In Between Linked Lists You are given two linked lists: list1 and list2 of sizes n and m respectively. | Medium | Likely | linked-list | Solve |
Validate Binary Search Tree Given the root of a binary tree, determine if it is a valid binary search tree (BST). | Medium | Likely | treedepth-first-searchbinary-search-tree | Solve |
Word Search Given an m x n grid of characters board and a string word, return true if word exists in the grid. | Medium | Likely | arraystringbacktracking | Solve |
Longest Common Subsequence Given two strings text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0. | Medium | Likely | stringdynamic-programming | Solve |
Construct String With Repeat Limit
SolveYou are given a string s and an integer repeatLimit. Construct a new string repeatLimitedString using the characters of s such that no letter appears more than...
Restore IP Addresses
SolveA valid IP address consists of exactly four integers separated by single dots. Each integer is between 0 and 255 (inclusive) and cannot have leading zeros.
Find the Town Judge
SolveIn a town, there are n people labeled from 1 to n. There is a rumor that one of these people is secretly the town judge.
Reverse Nodes in k-Group
SolveGiven the head of a linked list, reverse the nodes of the list k at a time, and return the modified list.
Reverse Linked List II
SolveGiven the head of a singly linked list and two integers left and right where left <= right, reverse the nodes of the list from position left to position right,...
Reorder List
SolveYou are given the head of a singly linked-list. The list can be represented as:
Contains Duplicate II
SolveGiven an integer array nums and an integer k, return true if there are two distinct indices i and j in the array such that nums[i] == nums[j] and abs(i - j) <=...
Rotated Digits
SolveAn integer x is a good if after rotating each digit individually by 180 degrees, we get a valid number that is different from x. Each digit must be rotated - we...
Remove Linked List Elements
SolveGiven the head of a linked list and an integer val, remove all the nodes of the linked list that has Node.val == val, and return the new head.
LRU Cache
SolveDesign a data structure that follows the constraints of a Least Recently Used (LRU) cache.
Search in Rotated Sorted Array
SolveThere is an integer array nums sorted in ascending order (with distinct values).
Missing Number
SolveGiven an array nums containing n distinct numbers in the range [0, n], return the only number in the range that is missing from the array.
Maximum Depth of Binary Tree
SolveGiven the root of a binary tree, return its maximum depth.
Merge Two Sorted Lists
SolveYou are given the heads of two sorted linked lists list1 and list2.
Course Schedule II
SolveThere are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1. You are given an array prerequisites where prerequisites[i] = [ai, b...
Binary Tree Maximum Path Sum
SolveA path in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an edge connecting them. A node can only appear in the sequ...
Maximum Units on a Truck
SolveYou are assigned to put some amount of boxes onto one truck. You are given a 2D array boxTypes, where boxTypes[i] = [numberOfBoxesi, numberOfUnitsPerBoxi]:
Kth Largest Element in a Stream
SolveYou are part of a university admissions office and need to keep track of the kth highest test score from applicants in real-time. This helps to determine cut-of...
Palindromic Substrings
SolveGiven a string s, return the number of palindromic substrings in it.
Flatten a Multilevel Doubly Linked List
SolveYou are given a doubly linked list, which contains nodes that have a next pointer, a previous pointer, and an additional child pointer. This child pointer may o...
Search a 2D Matrix
SolveYou are given an m x n integer matrix matrix with the following two properties:
Integer to Roman
SolveSeven different symbols represent Roman numerals with the following values:
Contains Duplicate
SolveGiven an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.
Find the Winner of the Circular Game
SolveThere are n friends that are playing a game. The friends are sitting in a circle and are numbered from 1 to n in clockwise order. More formally, moving clockwis...
Best Time to Buy and Sell Stock
SolveYou are given an array prices where prices[i] is the price of a given stock on the ith day.
Implement Trie (Prefix Tree)
SolveA trie (pronounced as "try") or prefix tree is a tree data structure used to efficiently store and retrieve keys in a dataset of strings. There are various appl...
Path Sum II
SolveGiven the root of a binary tree and an integer targetSum, return all root-to-leaf paths where the sum of the node values in the path equals targetSum. Each path...
Kth Missing Positive Number
SolveGiven an array arr of positive integers sorted in a strictly increasing order, and an integer k.
Top K Frequent Elements
SolveGiven an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order.
Remove All Occurrences of a Substring
SolveGiven two strings s and part, perform the following operation on s until all occurrences of the substring part are removed:
Merge In Between Linked Lists
SolveYou are given two linked lists: list1 and list2 of sizes n and m respectively.
Validate Binary Search Tree
SolveGiven the root of a binary tree, determine if it is a valid binary search tree (BST).
Word Search
SolveGiven an m x n grid of characters board and a string word, return true if word exists in the grid.
Longest Common Subsequence
SolveGiven two strings text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0.
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent Arista Networks interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Arista Networks interviews focus heavily on array, hash-table, string problems. If you're short on time, these are the categories to prioritize. The problems on this page are sorted by frequency, so start from the top and work your way down.
Beyond solving problems, practice explaining your approach. Arista Networks interviewers care about your thought process - how you break down a problem, consider edge cases, and evaluate tradeoffs between solutions. A clean O(n) solution you can explain clearly beats an O(log n) solution you can't articulate.
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Arista Networks has been reported to ask 34 distinct coding problems. The most common topics are array, hash-table, string. 11 are Easy difficulty, 21 are Medium, and 2 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
Based on 34 reported problems, Arista Networks interviews are easier than average - only 6% Hard compared to 18% across all companies. 62% of questions are Medium difficulty. Focus on the high-frequency Medium problems first, then work through the Hard ones.
Start with the highest-frequency problems listed on this page. Focus on the core topics: array, hash-table, string. Practice solving them under time pressure and explaining your approach out loud. Mock interviews with AI can simulate the real experience.
Simulate a real Arista Networks coding interview with an AI interviewer. Get a scorecard with specific feedback on your problem-solving, code quality, and communication.
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