Since the job location is Beijing, HR required to go to the site for an interview after communication.

One side (spot side)

Since most of the principles of the field need to be explained by hand.

1, supervised learning unsupervised learning what difference, word2vec belongs to what type

2, XGB, GBDT what difference

3, L1, L2 regular principle, difference

4. How to use L1 regular in XGB

5, How to implement list in Python

What’s the difference between List dict

7. Sort dict by hand

8. Introduce the project and ask some more questions from the project

The second interview (on-site interview) the second interview brother was temporarily called, did not read my resume, on the resume of the project to discuss, discuss the way to achieve.

Three sides (site side)

1. Introduce yourself

2. Introduce the project

Boosting Bagging Stacking Principle

4, Stacking blending

5. Analyze why XGB is used (hint, compare from feature dimension, sample dimension, etc.)

6. Judgment method of overfitting

7. How to solve overfitting

8. Probability X is a random variable that produces 1,1-p and 0 with probability P, and generates a number 1-n with equal probability X

9, handwritten code two sort linked list merge

Four sides (field side)

1. Introduce yourself

2. Introduce the project

The KTH largest number in the array of handwritten codes

4. Time complexity of constructing heap

Five intersecting surfaces (video surfaces)

1. Introduce yourself

2. Usual results

3. Key-value data structures in Python

4. How to implement dict bottom layer

5. How to resolve hash conflicts

6. Examples of unsupervised learning

7. Explain the K-means principle

8. Calculation method of distance

9. How to choose a supervised learning model

10. Scenario C Know all the information and recommend restaurants to users

11, algorithm problem two 300G large files, find the intersection of two files

Six HR interviews (telephone interview)

1. Introduce yourself

2. What offers did you get and why did you choose Ali

3. What are the advantages and disadvantages

3, personality, personality, what shortcomings

4. What did you learn from the study and the interview

5. What are the salary requirements

Seven director’s Face (site face)

The director interview was the most difficult in the history, and the whole process was very confusing. Every question was not answered until the interview lasted about 2 hours.

1. Introduce the project

2. Introduce the paper in detail. My thesis direction is traffic

3, the introduction of the competition, the questions are from the competition, the project

4. Analyze the principle of XGB in detail, how to choose the splitting point, why to use the second-order Taylor expansion, and how to express the regular term in XGB. L1, L2 regular difference (I use probability and optimization theory analysis, the director asked me from gradient descent to explain why L1 sparse), L1 regular how to find the gradient. XGB, GBDT difference, GBDT why gradient, gradient with what benefits. Finally, I asked about the division of labor in the team.

5. Algorithm problem array and maximum subsequence

Lots of details. That’s about it. Hope you all find your dream job ~~

Gold-digging techniques: link to juejin.cn/post/1