Problem database last updated: June 20, 2025
28 problems · 2 Easy, 20 Medium, 6 Hard · Ranked #68 of 458
2 Easy
7% · avg 23%
20 Medium
71% · avg 59%
6 Hard
21% · avg 18%
Based on 28 reported problems, Anduril interviews are in line with industry averages - 21% Hard vs 18% overall. The majority (71%) 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, Anduril puts unusual emphasis on topological-sort (7.1% of problems, 6.1x the industry average), breadth-first-search (25% of problems, 3x the industry average), matrix (25% of problems, 2.8x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are array (60.7%), depth-first-search (25%), breadth-first-search (25%), matrix (25%). Problems below are sorted by frequency, the ones at the top are asked most often.
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
Number of Islands Given an m x n 2D binary grid grid which represents a map of '1's (land) and '0's (water), return the number of islands. | Medium | Very Likely | arraydepth-first-searchbreadth-first-search | Solve |
Video Stitching You are given a series of video clips from a sporting event that lasted time seconds. These video clips can be overlapping with each other and have varying leng... | Medium | Very Likely | arraydynamic-programminggreedy | Solve |
Maximum Number of Visible Points You are given an array points, an integer angle, and your location, where location = [posx, posy] and points[i] = [xi, yi] both denote integral coordinates on t... | Hard | Very Likely | arraymathgeometry | Solve |
Group Anagrams Given an array of strings strs, group the anagrams together. You can return the answer in any order. | Medium | Very Likely | arrayhash-tablestring | Solve |
Course Schedule 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 | Very Likely | depth-first-searchbreadth-first-searchgraph | Solve |
Heaters Winter is coming! During the contest, your first job is to design a standard heater with a fixed warm radius to warm all the houses. | Medium | Very Likely | arraytwo-pointersbinary-search | Solve |
Daily Temperatures Given an array of integers temperatures represents the daily temperatures, return an array answer such that answer[i] is the number of days you have to wait aft... | Medium | Very Likely | arraystackmonotonic-stack | Solve |
Find Median from Data Stream The median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value, and the median is the mean of the two midd... | Hard | Very Likely | two-pointersdesignsorting | 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 | Very Likely | depth-first-searchbreadth-first-searchgraph | Solve |
Search Suggestions System You are given an array of strings products and a string searchWord. | Medium | Likely | arraystringbinary-search | Solve |
Merge Intervals Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cove... | Medium | Likely | arraysorting | Solve |
Making A Large Island You are given an n x n binary matrix grid. You are allowed to change at most one 0 to be 1. | Hard | Likely | arraydepth-first-searchbreadth-first-search | Solve |
Flip Equivalent Binary Trees For a binary tree T, we can define a flip operation as follows: choose any node, and swap the left and right child subtrees. | Medium | Likely | treedepth-first-searchbinary-tree | Solve |
Flatten Binary Tree to Linked List Given the root of a binary tree, flatten the tree into a "linked list": | Medium | Likely | linked-liststacktree | Solve |
Basic Calculator II Given a string s which represents an expression, evaluate this expression and return its value. | Medium | Likely | mathstringstack | Solve |
Merge k Sorted Lists You are given an array of k linked-lists lists, each linked-list is sorted in ascending order. | Hard | Likely | linked-listdivide-and-conquerheap-priority-queue | Solve |
Race Car Your car starts at position 0 and speed +1 on an infinite number line. Your car can go into negative positions. Your car drives automatically according to a seq... | Hard | Likely | dynamic-programming | Solve |
Valid Parentheses Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. | Easy | Likely | stringstack | Solve |
Search in Rotated Sorted Array There is an integer array nums sorted in ascending order (with distinct values). | Medium | Likely | arraybinary-search | Solve |
Move Zeroes Given an integer array nums, move all 0's to the end of it while maintaining the relative order of the non-zero elements. | Easy | Likely | arraytwo-pointers | Solve |
Time Based Key-Value Store Design a time-based key-value data structure that can store multiple values for the same key at different time stamps and retrieve the key's value at a certain... | Medium | Likely | hash-tablestringbinary-search | Solve |
Rotting Oranges You are given an m x n grid where each cell can have one of three values: | Medium | Likely | arraybreadth-first-searchmatrix | Solve |
Find the Duplicate Number Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive. | Medium | Likely | arraytwo-pointersbinary-search | Solve |
Game of Life According to Wikipedia's article: "The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway... | Medium | Likely | arraymatrixsimulation | Solve |
Minesweeper Let's play the minesweeper game (Wikipedia, online game)! | Medium | Likely | arraydepth-first-searchbreadth-first-search | Solve |
Snakes and Ladders You are given an n x n integer matrix board where the cells are labeled from 1 to n2 in a Boustrophedon style starting from the bottom left of the board (i.e. b... | Medium | Likely | arraybreadth-first-searchmatrix | Solve |
Basic Calculator Given a string s representing a valid expression, implement a basic calculator to evaluate it, and return the result of the evaluation. | Hard | Likely | mathstringstack | Solve |
Spiral Matrix Given an m x n matrix, return all elements of the matrix in spiral order. | Medium | Likely | arraymatrixsimulation | Solve |
Number of Islands
SolveGiven an m x n 2D binary grid grid which represents a map of '1's (land) and '0's (water), return the number of islands.
Video Stitching
SolveYou are given a series of video clips from a sporting event that lasted time seconds. These video clips can be overlapping with each other and have varying leng...
Maximum Number of Visible Points
SolveYou are given an array points, an integer angle, and your location, where location = [posx, posy] and points[i] = [xi, yi] both denote integral coordinates on t...
Group Anagrams
SolveGiven an array of strings strs, group the anagrams together. You can return the answer in any order.
Course Schedule
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...
Heaters
SolveWinter is coming! During the contest, your first job is to design a standard heater with a fixed warm radius to warm all the houses.
Daily Temperatures
SolveGiven an array of integers temperatures represents the daily temperatures, return an array answer such that answer[i] is the number of days you have to wait aft...
Find Median from Data Stream
SolveThe median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value, and the median is the mean of the two midd...
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...
Search Suggestions System
SolveYou are given an array of strings products and a string searchWord.
Merge Intervals
SolveGiven an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cove...
Making A Large Island
SolveYou are given an n x n binary matrix grid. You are allowed to change at most one 0 to be 1.
Flip Equivalent Binary Trees
SolveFor a binary tree T, we can define a flip operation as follows: choose any node, and swap the left and right child subtrees.
Flatten Binary Tree to Linked List
SolveGiven the root of a binary tree, flatten the tree into a "linked list":
Basic Calculator II
SolveGiven a string s which represents an expression, evaluate this expression and return its value.
Merge k Sorted Lists
SolveYou are given an array of k linked-lists lists, each linked-list is sorted in ascending order.
Race Car
SolveYour car starts at position 0 and speed +1 on an infinite number line. Your car can go into negative positions. Your car drives automatically according to a seq...
Valid Parentheses
SolveGiven a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
Search in Rotated Sorted Array
SolveThere is an integer array nums sorted in ascending order (with distinct values).
Move Zeroes
SolveGiven an integer array nums, move all 0's to the end of it while maintaining the relative order of the non-zero elements.
Time Based Key-Value Store
SolveDesign a time-based key-value data structure that can store multiple values for the same key at different time stamps and retrieve the key's value at a certain...
Rotting Oranges
SolveYou are given an m x n grid where each cell can have one of three values:
Find the Duplicate Number
SolveGiven an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive.
Game of Life
SolveAccording to Wikipedia's article: "The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway...
Minesweeper
SolveLet's play the minesweeper game (Wikipedia, online game)!
Snakes and Ladders
SolveYou are given an n x n integer matrix board where the cells are labeled from 1 to n2 in a Boustrophedon style starting from the bottom left of the board (i.e. b...
Basic Calculator
SolveGiven a string s representing a valid expression, implement a basic calculator to evaluate it, and return the result of the evaluation.
Spiral Matrix
SolveGiven an m x n matrix, return all elements of the matrix in spiral order.
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent Anduril interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Anduril interviews focus heavily on array, depth-first-search, breadth-first-search 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. Anduril 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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Anduril has been reported to ask 28 distinct coding problems. The most common topics are array, depth-first-search, breadth-first-search. 2 are Easy difficulty, 20 are Medium, and 6 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
Based on 28 reported problems, Anduril interviews are in line with industry averages - 21% Hard vs 18% overall. 71% 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, depth-first-search, breadth-first-search. Practice solving them under time pressure and explaining your approach out loud. Mock interviews with AI can simulate the real experience.
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