Liftoff coding interview
questions, leaked.
4 problems reported across recent Liftoff interviews. Top patterns: array, backtracking, matrix. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Liftoff's assessment is small but sharp. Four problems total, and three of them are medium difficulty. You're looking at array manipulation as the core skill they're testing, but the problems themselves chain together multiple patterns. Diagonal Traverse and its sequel form a bloc that demands you think in 2D space and handle traversal order correctly. Random Pick with Weight is the curveball that blends math, prefix sums, and binary search into one problem. N-Queens II is the hard one, and it's pure backtracking. If you blank mid-assessment, StealthCoder runs invisibly during your screen share and surfaces working code in seconds.
Top problems at Liftoff
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Diagonal Traverse | MEDIUM | 100.0 | 63% | Array · Matrix · Simulation |
| 02 | Random Pick with Weight | MEDIUM | 89.7 | 48% | Array · Math · Binary Search |
| 03 | N-Queens II | HARD | 86.0 | 77% | Backtracking |
| 04 | Diagonal Traverse II | MEDIUM | 75.7 | 58% | Array · Sorting · Heap (Priority Queue) |
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 Liftoff OA. The proctor cannot see it. Screen share cannot detect it. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage.
Get StealthCoder- array3 · 75%
- backtracking1 · 25%
- matrix1 · 25%
- simulation1 · 25%
- sorting1 · 25%
- heap priority queue1 · 25%
- math1 · 25%
- binary search1 · 25%
- prefix sum1 · 25%
- randomized1 · 25%
Array problems appear in three of four questions, so drilling array traversal and 2D indexing first pays off immediately. The topic spread reveals a pattern: Liftoff isn't testing deep algorithmic knowledge across ten domains. They're testing how you combine adjacent concepts. Diagonal Traverse II adds sorting and heaps to the mix. Random Pick with Weight forces you to link randomization, prefix sums, and binary search. This isn't a breadth test. It's depth wrapped in medium-difficulty language. Backtracking (N-Queens II) sits alone as the hard outlier, which means you either nail it or you don't. Spend your prep on array logic and the prefix-sum plus binary-search pattern. Hit N-Queens only after arrays feel automatic. StealthCoder is your hedge on N-Queens or any problem where you hit the wall on traversal order mid-OA.
Companies with similar patterns
If you prepped for Liftoff, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Liftoff.
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. Built by an engineer who got tired of watching his cohort grind for six months and still get filtered at the OA stage. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Liftoff interview FAQ
How many array problems should I solve before Liftoff's OA?+
Array is in 3 of 4 problems reported. Spend at least half your prep time on 2D array traversal, boundary handling, and index logic. Both Diagonal Traverse versions are likely you'll see, so drill those patterns until they're automatic. Skip breadth and go deep on the patterns you see here.
Is backtracking really required, or can I skip N-Queens prep?+
One of four problems is N-Queens II, a hard backtracking problem. It's not optional if you want full points. That said, backtracking doesn't appear anywhere else in the data, so treat it as a focused spike. Learn the template, solve N-Queens I first, then tackle N-Queens II.
What order should I drill the four problems?+
Start with Diagonal Traverse (medium, pure array logic). Move to Diagonal Traverse II (adds sorting and heaps). Then Random Pick with Weight (hardest conceptually because it chains multiple topics). Save N-Queens II for last because it's isolated and hard. This builds momentum and leaves backtracking as your final gear-up.
Do I need to be strong in math and binary search for this OA?+
Random Pick with Weight demands both. It's one of four problems, so yes, practice that combination until you can code it under pressure. Math alone isn't tested elsewhere, but binary search plus prefix sum is the skeleton of that problem.
Is one week enough to prep for Liftoff's OA?+
Yes. Four problems, three medium and one hard. You have time if you focus. Drill array traversal and 2D logic hard for three days. Spend two days on Random Pick with Weight (prefix sum, binary search, randomization). Use the remaining days on N-Queens II. You're not learning ten topics. You're mastering four specific problems.