This week, I guided my students through TikTok's SDE Online Assessment (OA), and the entire set of problems felt very smooth.
I completed all four questions in 28 minutes with a full AC on the first try.
Below, I’m sharing the problem details and my reflections.
Monotonic Triplets
Description:
Given an integer array arr, determine if each consecutive triplet forms a monotonic subsequence (strictly increasing or strictly decreasing).
Return 1 if it is monotonic, otherwise 0, in an array of length arr.length - 2.
Solution Idea:
Iterate through all triplets with simple conditional checks.
Complexity:
O(n) — linear scan, no tricky edge cases.
Reflection:
A smooth warm-up question focusing on array iteration and conditionals.
Deck Shuffle
Description:
You have a deck of cards numbered from 1 to n in some order.
You may perform one operation: take k cards (0 ≤ k ≤ n-1) from the top and move them to the bottom.
Check if, after one operation, the deck can be sorted in ascending order.
Solution Idea:
Simulate all possible k values and verify if any operation produces a sorted deck.
Complexity:
O(n²) worst case (can be optimized with modular checks).
Reflection:
Looks abstract but is highly approachable once you model the rotation.
A great test of simulation and boundary condition awareness.
Race Elimination
Description:
In a racing competition, all drivers complete qualifying laps.
Each lap, the driver(s) with the slowest “best” time (highest personal best) are eliminated.
If multiple drivers tie for the slowest time, they are all eliminated.
Given a 2D string array with each driver’s name and lap times,
return the drivers’ names in elimination order, followed by the remaining driver.
Solution Idea:
- Use a dictionary to track each driver’s best time.
- After each round, eliminate the driver(s) with the slowest best time.
- Continue until one remains.
Complexity:
O(n × m log n) due to sorting per elimination phase.
Reflection:
Tests your ability to simulate state updates and manage sorting logic cleanly.
Counting Black Squares
Description:
Given a grid of black and white cells and an array black containing coordinates of all black cells,
count the number of 2×2 submatrices with exactly blackCount black cells
(where 0 ≤ blackCount ≤ 4).
Return a length-5 array with the counts.
Solution Idea:
Enumerate all valid 2×2 submatrix starting positions.
Use a hash set for O(1) lookups of black cell coordinates.
Complexity:
O(rows × cols)
Reflection:
A clean grid enumeration problem.
Strong focus on spatial reasoning and counting patterns.
Fall Recruitment Trends
TikTok’s OA this year leans toward conventional problem types with no algorithmic traps.
The difficulty is well-distributed across:
- Basic array logic
- Simulation and enumeration
- State updates with sorting
- 2D traversal and counting
Compared to last year’s question bank, this round emphasizes coding correctness
and implementation accuracy over tricky or deceptive logic.
Programhelp Real-Time Stealth Assistance Experience
If you’re preparing for TikTok’s OA or other major companies’ assessments,
practicing similar problem types in advance is key.
Programhelp offers:
- Real-time voice reminders for critical tips (e.g., “You reversed the condition”)
- Pre-verified logic frameworks for simulation problems
- Multi-platform compatibility (CodeSignal, HackerRank, Codility)
- 100% stealth operations for safety
We’ve helped numerous students ace OAs for TikTok, Uber, Capital One, Snowflake, and more — across fall, spring, and internal referral testing phases.
Top comments (0)