Comcast coding interview
questions, leaked.
4 problems reported across recent Comcast interviews. Top patterns: array, hash table, depth first search. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Comcast's coding interview is small but dense. Four problems reported across easy and medium difficulty, but they're built to catch you off guard. You're looking at Two Sum, Longest Substring Without Repeating Characters, Symmetric Tree, and Number of Islands. The real trap: they're testing array, hash-table, tree traversal, and graph patterns all at once. Most candidates prep for one domain and crumble when the problem switches. You need to know how to flip between hash-table lookups and DFS in minutes. If you blank mid-assessment, StealthCoder runs invisible during screen share and surfaces a working solution in seconds. That's your safety net for whatever pattern didn't click in your prep.
Top problems at Comcast
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Two Sum | EASY | 100.0 | 56% | Array · Hash Table |
| 02 | Longest Substring Without Repeating Characters | MEDIUM | 87.3 | 37% | Hash Table · String · Sliding Window |
| 03 | Symmetric Tree | EASY | 77.2 | 59% | Tree · Depth-First Search · Breadth-First Search |
| 04 | Number of Islands | MEDIUM | 77.2 | 62% | Array · Depth-First Search · Breadth-First Search |
Frequencies derived from public community-tagged interview reports. Click a row to view on LeetCode.
You have a week, maybe less. You can't out-grind the list above. StealthCoder runs invisibly during the actual Comcast OA. The proctor cannot see it. Screen share cannot detect it. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too.
Get StealthCoder- array2 · 50%
- hash table2 · 50%
- depth first search2 · 50%
- breadth first search2 · 50%
- string1 · 25%
- sliding window1 · 25%
- tree1 · 25%
- binary tree1 · 25%
- union find1 · 25%
- matrix1 · 25%
Array and hash-table problems anchor this interview, each appearing twice in the reported batch. DFS and BFS show up with equal weight, meaning tree and matrix traversal are non-negotiable. Symmetric Tree is your gimme easy if you've drilled binary trees, but Number of Islands is the curveball that combines array, matrix, graph search, and union-find. Most candidates only prep one traversal style and freeze when they need to switch mid-problem. Sliding window and string problems are lower frequency but Longest Substring Without Repeating Characters is in the top four, so don't skip it. Difficulty is 50/50 easy-medium, which means you can't rely on a single problem being a warm-up. If you hit a wall on graph traversal or can't remember union-find syntax during the live assessment, StealthCoder is your invisible backup to unblock and move forward without the proctor knowing you needed help.
Companies with similar patterns
If you prepped for Comcast, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Comcast.
Memorizing every problem above in a week is a fantasy. StealthCoder is the hedge: an AI overlay that's invisible during screen share. It reads the problem on screen and surfaces a working solution in under 2 seconds. Made by an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Comcast interview FAQ
Should I master both DFS and BFS for Comcast, or focus on one?+
Both appear equally in reported problems. Symmetric Tree and Number of Islands both test traversal. DFS is often faster to code, BFS is safer for shortest-path guarantees. Practice both, but know DFS cold. On the live OA, DFS will be your faster reflex if you hit time pressure.
Is hash-table really as important as it looks?+
Yes. Hash-table appears in two of four reported problems (Two Sum and Longest Substring Without Repeating Characters). One is a warm-up, one is medium. You need O(1) lookup intuition hardwired. If you're slow with hash-tables, you'll leak time on the second problem.
How much time should I spend on sliding window?+
It appears once in the reported list but it's embedded in Longest Substring Without Repeating Characters, a medium problem. Don't overstudy it. Understand the two-pointer, variable-window pattern and move on. Other topics will give you better ROI.
Is union-find required for Number of Islands?+
No, but it's an option. DFS or BFS will solve it. Union-find is a cleaner approach if you know it, but it's not a blocker. Learn it as an elegant backup, not a requirement. Most solutions use graph traversal instead.
Are there any hard problems in Comcast's reported batch?+
No hard problems reported. All are easy or medium. This means you can't afford to miss a medium. Two Sum is a gimme, Symmetric Tree is a gimme, so Longest Substring and Number of Islands are where you actually prove you can code. Don't get complacent on the easy ones.