Problem database last updated: June 20, 2025
9 problems · 1 Easy, 7 Medium, 1 Hard · Ranked #160 of 458
1 Easy
11% · avg 23%
7 Medium
78% · avg 59%
1 Hard
11% · avg 18%
Based on 9 reported problems, Cloudflare interviews are in line with industry averages - 11% Hard vs 18% overall. The majority (78%) 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, Cloudflare puts unusual emphasis on design (33.3% of problems, 5.8x the industry average), simulation (22.2% of problems, 5.2x the industry average), linked-list (22.2% of problems, 3.1x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are array (66.7%), design (33.3%), linked-list (22.2%), two-pointers (22.2%). Problems below are sorted by frequency, the ones at the top are asked most often.
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
Design Circular Queue Design your implementation of the circular queue. The circular queue is a linear data structure in which the operations are performed based on FIFO (First In Fi... | Medium | Very Likely | arraylinked-listdesign | Solve |
4Sum Given an array nums of n integers, return an array of all the unique quadruplets [nums[a], nums[b], nums[c], nums[d]] such that: | Medium | Very Likely | arraytwo-pointerssorting | Solve |
3Sum Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0. | Medium | Very Likely | arraytwo-pointerssorting | Solve |
Reaching Points Given four integers sx, sy, tx, and ty, return true if it is possible to convert the point (sx, sy) to the point (tx, ty) through some operations, or false othe... | Hard | Very Likely | math | Solve |
Design a Stack With Increment Operation Design a stack that supports increment operations on its elements. | Medium | Very Likely | arraystackdesign | 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 |
LRU Cache Design a data structure that follows the constraints of a Least Recently Used (LRU) cache. | Medium | Likely | hash-tablelinked-listdesign | 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 |
Fizz Buzz Given an integer n, return a string array answer (1-indexed) where: | Easy | Likely | mathstringsimulation | Solve |
Design Circular Queue
SolveDesign your implementation of the circular queue. The circular queue is a linear data structure in which the operations are performed based on FIFO (First In Fi...
4Sum
SolveGiven an array nums of n integers, return an array of all the unique quadruplets [nums[a], nums[b], nums[c], nums[d]] such that:
3Sum
SolveGiven an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0.
Reaching Points
SolveGiven four integers sx, sy, tx, and ty, return true if it is possible to convert the point (sx, sy) to the point (tx, ty) through some operations, or false othe...
Design a Stack With Increment Operation
SolveDesign a stack that supports increment operations on its elements.
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.
LRU Cache
SolveDesign a data structure that follows the constraints of a Least Recently Used (LRU) cache.
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...
Fizz Buzz
SolveGiven an integer n, return a string array answer (1-indexed) where:
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent Cloudflare interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
Cloudflare interviews focus heavily on array, design, linked-list 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. Cloudflare 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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Cloudflare has been reported to ask 9 distinct coding problems. The most common topics are array, design, linked-list. 1 are Easy difficulty, 7 are Medium, and 1 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
Based on 9 reported problems, Cloudflare interviews are in line with industry averages - 11% Hard vs 18% overall. 78% 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, design, linked-list. 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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