PayPal数据相关面经_PayPal数据相关面试真题及高频题

1.Calculating Rolling Sum for the Last 30 Days

2.Enhancing Fraud Detection: Efficient Challenge Authentication Methods

3.Detecting Fraudulent Transactions: Strategies and Techniques

4.Finding the First Missing Value in a Consecutive List.

5.Find the First Unique Character in a String

6.Count Strings Starting and Ending with a Vowel

7.Counting Valid Strings from String Array Based on Vowel Criteria

8.Counting Song Pairs with Sum Divisible by 60

9.Vowel Prefix Count in Queries

10.Max Positive Prefix Sum

11.Closest Numbers

12.Playlist Song Pairing

13.First Unique Character Function

14.Vowels Query Function

15.Maximize Positive Prefixes

16.Closest Numbers

17.Playlist Pairing

18.Whole Minute Dilemma

19.Maximize Positive Prefix Sums

20.Vowels Prefix Sum

21.Minute Dilemma

22.Vowels

23.Positive Prefixes

24.First Unique Character

25.Closest Number

26.Whole Minute Dilemma

27.SQL and coding interview round

28.SQL-focused interview round

29.Find the Xth Largest Element in an Array

30.How do you evaluate a model?

31.How do you deal with imbalanced data?

32.What is TFIDF and how is it used?

33.Difference between Bias and Variance?

34.What is the difference between Boosting and Bagging?

35.Explain the difference between a decision tree and RandomForest/LightGBM.

36.Sanity Check for Campaign Results

37.Designing an Experiment

38.SQL Window Functions

39.Implement a Transaction Filter Function

1. Calculating Rolling Sum for the Last 30 Days

求每天的前30天的rollling sum.

2. Enhancing Fraud Detection: Efficient Challenge Authentication Methods

detect fraud以后，需要给user send challenges：sms, email, ivr。brainstorm一下其他更好的challenge authentication的方法，从cost,effective考虑。.

3. Detecting Fraudulent Transactions: Strategies and Techniques

给一些transactional的信息，怎么判断是不是fraud

4. Finding the First Missing Value in a Consecutive List.

find 1st missing value in a consecutive list, like [1,2,4,5] --->3

5. Find the First Unique Character in a String

Given a string, find the index (1-based) of the first unique (only appears once) character. For instance, given the input 'banana', the output should be '1'. Describe how you would solve this problem and analyze the time and space complexity of your solution.