How often are these problems asked?
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent Karat interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Problem database last updated: June 20, 2025
K
Karat Coding Interview Questions
15 problems · 4 Easy, 9 Medium, 2 Hard · Ranked #109 of 458
Difficulty breakdown
4 Easy
27% · avg 23%
9 Medium
60% · avg 59%
2 Hard
13% · avg 18%
Top topics
array
80%
string
46.7%1.7x
hash-table
40%1.8x
matrix
40%4.5x
depth-first-search
26.7%2.9x
counting
20%6x
Interview profile
Based on 15 reported problems, Karat interviews are in line with industry averages - 13% Hard vs 18% overall. The majority (60%) 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, Karat puts unusual emphasis on topological-sort (13.3% of problems, 11.3x the industry average), counting (20% of problems, 6x the industry average), matrix (40% of problems, 4.5x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are array (80%), string (46.7%), hash-table (40%), matrix (40%). Problems below are sorted by frequency, the ones at the top are asked most often.
All 15 problems
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
Text Justification Given an array of strings words and a width maxWidth, format the text such that each line has exactly maxWidth characters and is fully (left and right) justifie... | Hard | Very Likely | arraystringsimulation | Solve |
Check if Every Row and Column Contains All Numbers An n x n matrix is valid if every row and every column contains all the integers from 1 to n (inclusive). | Easy | Very Likely | arrayhash-tablematrix | Solve |
Find Words That Can Be Formed by Characters You are given an array of strings words and a string chars. | Easy | Very Likely | arrayhash-tablestring | 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 | Very Likely | arraystringbacktracking | Solve |
Alert Using Same Key-Card Three or More Times in a One Hour Period LeetCode company workers use key-cards to unlock office doors. Each time a worker uses their key-card, the security system saves the worker's name and the time... | 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 | Likely | depth-first-searchbreadth-first-searchgraph | Solve |
Ransom Note Given two strings ransomNote and magazine, return true if ransomNote can be constructed by using the letters from magazine and false otherwise. | Easy | Likely | hash-tablestringcounting | 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 | Likely | arraydepth-first-searchbreadth-first-search | Solve |
Valid Sudoku Determine if a 9 x 9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules: | Medium | Likely | arrayhash-tablematrix | Solve |
Maximal Square Given an m x n binary matrix filled with 0's and 1's, find the largest square containing only 1's and return its area. | Medium | Likely | arraydynamic-programmingmatrix | 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 | Sometimes | depth-first-searchbreadth-first-searchgraph | Solve |
Two Sum Given an array of integers nums and an integer target, return the indices of the two numbers that add up to target. | Easy | Sometimes | arrayhash-map | Solve |
Word Search II Given an m x n board of characters and a list of strings words, return all words on the board. | Hard | Sometimes | arraystringbacktracking | Solve |
Subdomain Visit Count A website domain "discuss.leetcode.com" consists of various subdomains. At the top level, we have "com", at the next level, we have "leetcode.com" and at the lo... | Medium | Sometimes | arrayhash-tablestring | Solve |
Jump Game You are given an integer array nums. You are initially positioned at the array's first index, and each element in the array represents your maximum jump length... | Medium | Sometimes | arraydynamic-programminggreedy | Solve |
Text Justification
SolveGiven an array of strings words and a width maxWidth, format the text such that each line has exactly maxWidth characters and is fully (left and right) justifie...
HardVery Likely
arraystringsimulation
Check if Every Row and Column Contains All Numbers
SolveAn n x n matrix is valid if every row and every column contains all the integers from 1 to n (inclusive).
EasyVery Likely
arrayhash-tablematrix
Find Words That Can Be Formed by Characters
SolveYou are given an array of strings words and a string chars.
EasyVery Likely
arrayhash-tablestring
Word Search
SolveGiven an m x n grid of characters board and a string word, return true if word exists in the grid.
MediumVery Likely
arraystringbacktracking
Alert Using Same Key-Card Three or More Times in a One Hour Period
SolveLeetCode company workers use key-cards to unlock office doors. Each time a worker uses their key-card, the security system saves the worker's name and the time...
MediumVery Likely
arrayhash-tablestring
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...
MediumLikely
depth-first-searchbreadth-first-searchgraph
Ransom Note
SolveGiven two strings ransomNote and magazine, return true if ransomNote can be constructed by using the letters from magazine and false otherwise.
EasyLikely
hash-tablestringcounting
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.
MediumLikely
arraydepth-first-searchbreadth-first-search
Valid Sudoku
SolveDetermine if a 9 x 9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules:
MediumLikely
arrayhash-tablematrix
Maximal Square
SolveGiven an m x n binary matrix filled with 0's and 1's, find the largest square containing only 1's and return its area.
MediumLikely
arraydynamic-programmingmatrix
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...
MediumSometimes
depth-first-searchbreadth-first-searchgraph
Two Sum
SolveGiven an array of integers nums and an integer target, return the indices of the two numbers that add up to target.
EasySometimes
arrayhash-map
Word Search II
SolveGiven an m x n board of characters and a list of strings words, return all words on the board.
HardSometimes
arraystringbacktracking
Subdomain Visit Count
SolveA website domain "discuss.leetcode.com" consists of various subdomains. At the top level, we have "com", at the next level, we have "leetcode.com" and at the lo...
MediumSometimes
arrayhash-tablestring
Jump Game
SolveYou are given an integer array nums. You are initially positioned at the array's first index, and each element in the array represents your maximum jump length...
MediumSometimes
arraydynamic-programminggreedy
Preparing for your Karat coding interview
Karat interviews focus heavily on array, string, hash-table 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. Karat 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.
Looking for more companies? Browse all 458 companies in our directory, or sharpen your fundamentals with our free data structure visualizers and AI-powered DSA tutor.
Frequently Asked Questions
What coding problems does Karat ask in interviews?add
Karat has been reported to ask 15 distinct coding problems. The most common topics are array, string, hash-table. 4 are Easy difficulty, 9 are Medium, and 2 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
How hard are Karat coding interviews?add
Based on 15 reported problems, Karat interviews are in line with industry averages - 13% Hard vs 18% overall. 60% of questions are Medium difficulty. Focus on the high-frequency Medium problems first, then work through the Hard ones.
How should I prepare for a Karat coding interview?add
Start with the highest-frequency problems listed on this page. Focus on the core topics: array, string, hash-table. 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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