Problem database last updated: June 20, 2025
25 problems · 7 Easy, 12 Medium, 6 Hard · Ranked #81 of 458
7 Easy
28% · avg 23%
12 Medium
48% · avg 59%
6 Hard
24% · avg 18%
Based on 25 reported problems, Palantir Technologies interviews are slightly harder than average - 24% Hard vs 18% across all companies.
Compared to the industry average, Palantir Technologies puts unusual emphasis on rolling-hash (8% of problems, 21.4x the industry average), hash-function (8% of problems, 13.8x the industry average), merge-sort (8% of problems, 10.9x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are array (72%), sorting (28%), string (20%), hash-table (20%). Problems below are sorted by frequency, the ones at the top are asked most often.
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
Find Beautiful Indices in the Given Array I You are given a 0-indexed string s, a string a, a string b, and an integer k. | Medium | Very Likely | two-pointersstringbinary-search | Solve |
Find Beautiful Indices in the Given Array II You are given a 0-indexed string s, a string a, a string b, and an integer k. | Hard | Very Likely | two-pointersstringbinary-search | Solve |
Integer to English Words Convert a non-negative integer num to its English words representation. | Hard | Very Likely | mathstringrecursion | Solve |
Minimum Time Difference Given a list of 24-hour clock time points in "HH:MM" format, return the minimum minutes difference between any two time-points in the list. | Medium | Very Likely | arraymathstring | Solve |
LRU Cache Design a data structure that follows the constraints of a Least Recently Used (LRU) cache. | Medium | Very Likely | hash-tablelinked-listdesign | 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 |
Range Sum Query - Immutable Given an integer array nums, handle multiple queries of the following type: | Easy | Very Likely | arraydesignprefix-sum | Solve |
Selling Pieces of Wood You are given two integers m and n that represent the height and width of a rectangular piece of wood. You are also given a 2D integer array prices, where price... | Hard | Very Likely | arraydynamic-programmingmemoization | 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 | Very Likely | arrayhash-tablesorting | Solve |
Single Number Given a non-empty array of integers nums, every element appears twice except for one. Find that single one. | Easy | Very Likely | arraybit-manipulation | Solve |
Contains Duplicate III You are given an integer array nums and two integers indexDiff and valueDiff. | Hard | Very Likely | arraysliding-windowsorting | Solve |
Check If It Is a Straight Line You are given an integer array coordinates, coordinates[i] = [x, y], where [x, y] represents the coordinate of a point. Check if these points make a straight li... | Easy | Very Likely | arraymathgeometry | 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 |
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 |
Construct Quad Tree Given a n n matrix grid of 0's and 1's only. We want to represent grid with a Quad-Tree. | Medium | Likely | arraydivide-and-conquertree | Solve |
Find Players With Zero or One Losses You are given an integer array matches where matches[i] = [winneri, loseri] indicates that the player winneri defeated player loseri in a match. | Medium | Likely | arrayhash-tablesorting | Solve |
Minimum Equal Sum of Two Arrays After Replacing Zeros You are given two arrays nums1 and nums2 consisting of positive integers. | Medium | Likely | arraygreedy | 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 | Sometimes | arraystackmonotonic-stack | 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 | Sometimes | arraydynamic-programming | Solve |
Flood Fill You are given an image represented by an m x n grid of integers image, where image[i][j] represents the pixel value of the image. You are also given three integ... | Easy | Sometimes | arraydepth-first-searchbreadth-first-search | Solve |
Trapping Rain Water II Given an m x n integer matrix heightMap representing the height of each unit cell in a 2D elevation map, return the volume of water it can trap after raining. | Hard | Sometimes | arraybreadth-first-searchheap-priority-queue | Solve |
Sort List Given the head of a linked list, return the list after sorting it in ascending order. | Medium | Sometimes | linked-listtwo-pointersdivide-and-conquer | Solve |
Accounts Merge Given a list of accounts where each element accounts[i] is a list of strings, where the first element accounts[i][0] is a name, and the rest of the elements are... | Medium | Sometimes | arrayhash-tablestring | Solve |
All Ancestors of a Node in a Directed Acyclic Graph You are given a positive integer n representing the number of nodes of a Directed Acyclic Graph (DAG). The nodes are numbered from 0 to n - 1 (inclusive). | Medium | Sometimes | depth-first-searchbreadth-first-searchgraph | Solve |
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 | Sometimes | arraydepth-first-searchbreadth-first-search | Solve |
Find Beautiful Indices in the Given Array I
SolveYou are given a 0-indexed string s, a string a, a string b, and an integer k.
Find Beautiful Indices in the Given Array II
SolveYou are given a 0-indexed string s, a string a, a string b, and an integer k.
Integer to English Words
SolveConvert a non-negative integer num to its English words representation.
Minimum Time Difference
SolveGiven a list of 24-hour clock time points in "HH:MM" format, return the minimum minutes difference between any two time-points in the list.
LRU Cache
SolveDesign a data structure that follows the constraints of a Least Recently Used (LRU) cache.
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) <=...
Range Sum Query - Immutable
SolveGiven an integer array nums, handle multiple queries of the following type:
Selling Pieces of Wood
SolveYou are given two integers m and n that represent the height and width of a rectangular piece of wood. You are also given a 2D integer array prices, where price...
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.
Single Number
SolveGiven a non-empty array of integers nums, every element appears twice except for one. Find that single one.
Contains Duplicate III
SolveYou are given an integer array nums and two integers indexDiff and valueDiff.
Check If It Is a Straight Line
SolveYou are given an integer array coordinates, coordinates[i] = [x, y], where [x, y] represents the coordinate of a point. Check if these points make a straight li...
Merge k Sorted Lists
SolveYou are given an array of k linked-lists lists, each linked-list is sorted in ascending order.
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...
Construct Quad Tree
SolveGiven a n n matrix grid of 0's and 1's only. We want to represent grid with a Quad-Tree.
Find Players With Zero or One Losses
SolveYou are given an integer array matches where matches[i] = [winneri, loseri] indicates that the player winneri defeated player loseri in a match.
Minimum Equal Sum of Two Arrays After Replacing Zeros
SolveYou are given two arrays nums1 and nums2 consisting of positive integers.
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...
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.
Flood Fill
SolveYou are given an image represented by an m x n grid of integers image, where image[i][j] represents the pixel value of the image. You are also given three integ...
Trapping Rain Water II
SolveGiven an m x n integer matrix heightMap representing the height of each unit cell in a 2D elevation map, return the volume of water it can trap after raining.
Sort List
SolveGiven the head of a linked list, return the list after sorting it in ascending order.
Accounts Merge
SolveGiven a list of accounts where each element accounts[i] is a list of strings, where the first element accounts[i][0] is a name, and the rest of the elements are...
All Ancestors of a Node in a Directed Acyclic Graph
SolveYou are given a positive integer n representing the number of nodes of a Directed Acyclic Graph (DAG). The nodes are numbered from 0 to n - 1 (inclusive).
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.
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent Palantir Technologies interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Palantir Technologies interviews focus heavily on array, sorting, 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. Palantir Technologies 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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Palantir Technologies has been reported to ask 25 distinct coding problems. The most common topics are array, sorting, string. 7 are Easy difficulty, 12 are Medium, and 6 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
Based on 25 reported problems, Palantir Technologies interviews are slightly harder than average - 24% Hard vs 18% across all companies. 48% 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, sorting, 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 Palantir Technologies coding interview with an AI interviewer. Get a scorecard with specific feedback on your problem-solving, code quality, and communication.
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