One-line takeaway on the Optiver OA: don't just grind LeetCode. It's a hybrid of Coding + Math/Mental math + Trading simulator, and each stage tests a different muscle. This playbook digests oavoservice student debriefs and breaks down where VO interview assist helps — and where it doesn't.
1. The OA structure (varies by role)
| Role | OA stages | Duration |
|---|---|---|
| Software Engineer Intern | Coding 1 + Coding 2 + Math | 90–120 min |
| Quantitative Trader Intern | Math + Trading + 8-sec mental | 60 min |
| Quant Researcher | Coding + Math + Stats | 120 min |
Three stage focuses:
- Coding — HackerRank, 2–3 LC Mediums
- Math / probability — multiple-choice + fill-in, includes 8-second mental
- Trading — proprietary simulator, prices move while you decide
2. Coding stage (HackerRank-style)
High-frequency themes
| Type | Frequency | Key |
|---|---|---|
| Arrays / sliding window | high | monotonic queue / two pointers |
| 2D grid / BFS | mid | template form |
| String parsing | mid | small state machine |
| Light design | mid | hash + heap |
Recall: order-book aggregation
Given a quote stream
quotes[i] = (t, side, price, qty)for one trading day, aggregate into 1-second buckets and emit per-second VWAP. For seconds with no fills, emit the previous VWAP.
from collections import defaultdict
def vwap_per_second(quotes):
bucket = defaultdict(lambda: [0.0, 0])
for t, side, price, qty in quotes:
sec = int(t)
bucket[sec][0] += price * qty
bucket[sec][1] += qty
if not bucket:
return []
secs = sorted(bucket.keys())
out = []
last = None
for s in range(secs[0], secs[-1] + 1):
if s in bucket and bucket[s][1] > 0:
last = bucket[s][0] / bucket[s][1]
out.append((s, last))
return out
Complexity: O(n + T). Trap: silent zero-quote seconds account for most lost points.
3. Math stage: 8-second mental + probability
8-second mental (Optiver signature)
Sample form:
0.04 × 25 + 1.5 = ?
1/8 + 3/16 = ?
17 × 23 = ?
8 seconds per question, 80 questions, ≥ 70 correct passes comfortably. The exam isn't testing knowledge — it's testing whether you stay calm.
Drill recipe: 200 questions a day for the week before the OA, pencil-paper, no calculator. Mental math is muscle memory.
Probability section (~10 questions)
Common types:
- Expected value (with conditioning)
- Monty Hall and variants
- Geometric / negative binomial
- Light martingale / random walk
- Bayesian inference
Recall (variant):
You flip a fair coin until HH appears. Expected number of flips?
Classical recursion. Let E be the expected count, E1 = expected count after the previous flip was H.
E1 = 1/2 × 1 + 1/2 × (1 + E)
E = 1/2 × (1 + E1) + 1/2 × (1 + E)
=> E = 6
If derivation isn't on the tip of your tongue, memorize a small set of canonical results — calmer than re-deriving on the clock.
4. Trading stage: live simulator
The most Optiver-flavored part. You face a simplified matching engine; the book moves in real time and you must:
- Quote bid / ask
- Take when you spot mispricing
- Risk-manage — a position cap; breach forces unwind plus penalty
Scoring playbook
- Watch 30–60 seconds first — learn this "stock's" rhythm
- Never carry a maxed book — when you hit half cap, trim
- Watch the clock — leave 10 seconds for liquidation
- Eat obvious mispricings — the simulator deliberately injects them
Edge sources:
- Market-making spread (high-frequency small)
- Mispricing arb (event-driven)
- Trend-following (small slice)
Trap: white-knuckling a losing position is the most common newbie failure — the PnL curve will punish you.
5. Score thresholds and pacing
| Stage | Pass line (student data) |
|---|---|
| Coding | 2 AC, partial 3rd |
| Mental math | ≥ 70 / 80 |
| Probability | ≥ 7 / 10 |
| Trading | Positive PnL + bounded drawdown |
Pacing tips:
- Snap-answer mental math, skip what you can't
- Skip stuck probability questions early; circle back
- Pre-rehearse the trading interface in your head — the first 10 seconds are decisive
6. VO Interview Assist for Optiver OA
oavoservice covers the full Optiver flow:
- Theme prediction: weekly mental-math + probability + coding theme refresh
- Timed mock: full 60 / 90 / 120-minute pressure runs
- Trading simulator drilling: similar-rules sandbox to build market-making instincts
- Live OA assist: mentor on-channel from link delivery to submission
- Trading Game (live): pre-round brief + live thinking cues + risk reminders
- HM: mock + reverse-question list + cadence calibration
End-to-end coverage from OA to Trading Game to HM, with tailored support per stage.
7. 4-week prep schedule
| Week | Focus |
|---|---|
| W1 | Mental math 200/day + 50 canonical probability problems |
| W2 | LC 30 (arrays / sliding / graphs) |
| W3 | Trading simulator drilling × 5 |
| W4 | Full OA mock × 2 + mental prep |
FAQ
Is Optiver OA hard?
Coding isn't. Mental math + Trading is the real filter. ~30% of students full-AC coding but miss mental-math.
Can I use pencil and paper for mental math?
Yes, but at 8 seconds per question, writing slows you down — most students stick to head math.
How deep does probability go?
Not PhD-level, but basic stochastic processes + EV + martingales must be solid.
Will I lose money on the trading simulator?
Often, especially first attempt. Run at least 5 simulator sessions — learn not to lose first, then to make.
What can VO Interview Assist do during Trading Game?
Pre-round brief, live thinking cues, risk reminders, and on-the-fly assist throughout the session. Mentor coverage spans OA → Trading Game → HM.
Preparing for Optiver OA / Trading Game?
oavoservice tracks Optiver OA themes continuously. Services: mental-math drills, probability bank, coding timed mock, trading simulator drilling, and VO interview assist.
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Contact
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