建议买书。
1) 红皮书Mark Joshi: "Quant Job Interviews: Questions and Answers". I
have heard very good things about this book.
2) 绿皮书Xinfeng Zhou, "A Practical Guide to Quantitative Finance
Interviews"
版上有很多题。
wilmott forum有不少brainteaser http://www.wilmott.com/categories.cfm?catid=26