高频题（0）
1. Your Top Proficient Programming Language?
What is the programming language that you have the most proficiency?
2. String Structure, Duplicate Finder, Light Switch Puzzle, Optimizing Fibonacci, Array Walk Circle Check
What does a string look like in c? i.e. data structure.
Given a string, find the first duplicate character in this string.
100 light bubbles, could be switched to on or off. The initial status is all off. The first round, switch every bubble, the second round, switch every two bubble, .....comes to the 100 round. Question: how to implement this process. Follow up: at the end, what bubbles are on.
Fibonacci series. Find f(n). If using recursive, how to optimize it.
Given an array, like [3,7,1,-2,4,5]. Initially at the A[0], the walk for A[i] steps, if positive, walk toward to right, if negative, walk toward to left. Determine whether it is a complete circle. Definition of complete circle: a. able to return to Arol. b.every point is visited. How to implement this, and what's the time complexity. Definition of complete circle: a. able to return to Ajol. b.every point is visited.
3. Interview Questions for Financial Engineer and Senior Application Developer.
1. 一个是financial engineer，另外一个是senior appliation developer
2. Financial engineer电面问题，包括python的decorator、ordered array to bst和list comprehension
3. dev的店面题，每轮三道leetcode题
4. Financial Engineer的onsite二轮问题，包括Monty Hall problem、sorted matrix找target、如何在pandas里面如何reindex以及fibnacci
5. Application Dev四轮问题，包括SQL找唯一、解释项目、tick tac toe、服务器慢如何找原因以及如何实现单机版in memory data store等
6. BB的FE是和quant一样的，想做quant的可以申请
7. R&D的位置全是考design
4. Solving Matrix Factorization for Sparse and Dense Data
matrixfactorization如果sparse怎样解如果dense呢？
5. Non-zero Eigenvalues in Covariance Matrix of Large Dataset
一个256x100000的dataset他的covariancematrix有多少>non-zero的eigenvalue。
