最近收到 Optiver 的 OA 邀请，整个流程挺有挑战性的，感觉像是考察你如何在高压下保持冷静，特别是算法和数学的结合。听说过不少小伙伴都卡在了数学题上，或者因为时间太紧而没来得及完成。
我在准备过程中，使用了 Programhelp 的无痕联机代写服务，帮助我在不被时间和细节拖慢的情况下，快速解决了编程难题，而且整个过程保持了我的个人代码风格。这次 OA 完成后，我终于顺利进入了下一轮面试，想分享给大家我的经历和一些备考建议，希望对你们有所帮助！
面试概况
公司：Optiver
时长：90 分钟
题量：3~4 道编程题，涉及算法、数学推理、数据结构等
难度：中等偏上，尤其是数学和编程结合的题目
平台：Optiver 提供的在线平台
语言：Python、C++（可以选择）
Optiver OA 真题解析
1. Two Sum Variation
So, the first problem is a variation of the classic “Two Sum” problem. You’re given an array, and you need to find two numbers that add up to a target value. But there’s a twist: you need to handle floating point precision properly, which is what trips most people up.
Example:
Input: arr = [1.2, 3.4, 2.1, 5.6], target = 5.3
Output: [0, 2]
How I Solved It:
I used a hash map to store the numbers and check if the complement exists. But since we’re dealing with floating point numbers, I made sure to round the numbers to a certain precision before storing them. This avoids issues with tiny precision errors that can sometimes happen with floating point numbers.
2. Binary Search for Missing Number
This one was pretty straightforward but tricky in its own way. You’re given an array from 1 to N with one number missing. You need to find that missing number using binary search.
Example:
Input: arr = [1, 2, 3, 5], N = 5
Output: 4
How I Solved It:
I used binary search on the array. The key idea here is that in a sorted array, the index of each element should match its value. If the index is smaller than the value, then the missing number is in the right half; if it’s bigger, the missing number is in the left half. This helps you narrow down the range quickly.
3. Math Puzzle – Probability Calculation
This one was a bit of a brain teaser. You had to calculate the probability of a certain event happening given a random experiment. It involved using combinatorics and probability formulas.
Example:
In a deck of 52 cards, calculate the probability of drawing at least one Ace in 5 draws without replacement.
How I Solved It:
Instead of directly calculating the probability of drawing at least one Ace, I first calculated the opposite — the probability of not drawing any Aces. Then I subtracted that from 1 to get the probability of getting at least one Ace. This is a common trick when dealing with probability problems.
FAQ
Q: Optiver OA 难吗？
A: 整体难度中等偏上，编程题没那么复杂，但数学题和算法题结合在一起，会让你在时间压力下很难保持稳定。时间管理特别重要！
Q: 如何提高解题速度？
A: 做题时，先看一遍所有题目，再做一个大致的时间分配。先做自己有把握的题目，困难的题目可以先跳过，避免在卡住的地方浪费太多时间。
Q: Programhelp 具体怎么帮你？
A: Programhelp 的无痕联机代写服务在我做题时帮我节省了不少时间，不仅在算法实现时给出了优化建议，还保证了代码的风格一致，这让我可以更专注于思考和测试。
你离Offer只有一步之遥
Optiver 的 OA 确实有点难度，但通过充分的准备、合理的时间管理，再加上 Programhelp 的帮助，我顺利完成了所有题目，并成功进入了下一轮面试。
如果你也在准备类似的 OA，特别是像 Optiver 这种要求全面的公司，不妨试试 Programhelp。我们的无痕联机代写服务，不仅能保证你的代码质量，还能帮助你在高压环境下保持冷静和自信，轻松应对每一轮挑战。
