Boston找DS/ML工作

最近复习了不少machine learning 的内容，收集了一些面经，分享如下。leetcode 刚开始刷。 有一起找工作的同学可以互相鼓励，多交流了。[hide=180]


面经分两大块：machinelearning questions 和coding questions.
. check 1point3acres for more.
Machine learning related questions:
-  Discuss how to predict the price of a hotel given data fromprevious
years
-  SVM formulation
-  Logistic regression
-  Regularization
-  Cost function of neural network
-  What is the difference between a generative and discriminativealgorithm
-  Relationship between kernel trick and dimension augmentation
-  What is PCA projection and why it can be solved by SVD  
-  Bag of Words (BoW) feature
-  Nonlinear dimension reduction (Isomap, LLE)
-  Supervised methods for dimension reduction
-  What is naive Bayes
-  Stochastic gradient / gradient descent
.1point3acres-  How to predict the age of a person given everyone’s phone call history
-  Variance and Bias (a very popular question, watch Andrew’s class)
-  Practices: When to collect more data / use more features / etc.(watch
Andrew’s class)
-  How to extract features of shoes
-  During linear regression, when using each attribute (dimension)
independently to predict the target value, you get a positive weight for
each attribute. However, when you combine all attributes to predict, you get
some large negative weights, why? How to solve it?
-  Cross Validation
-  Reservoir sampling
-  Explain the difference among decision tree, bagging and random forest
-  What is collaborative filtering
-  How to compute the average of a data stream (very easy, differentfrom
moving average)
-  Given a coin, how to pick 1 person from 3 persons with equalprobability.


Coding related questions:
-  Leetcode: Number of Islands
-  Given the start time and end time of each meeting, compute thesmallest
number of rooms to host these meetings. In other words, try to stuff as many
meetings in the same room as possible
-  Given an array of integers, compute the first two maximum products(乘积)
of any 3 elements (O(nlogn))
-  LeetCode: Reverse words in a sentence (follow up: do it in-place)
-  LeetCode: Word Pattern
-  Evaluate a formula represented as a string, e.g., “3 + (2 * (4 - 1) )”
-  Flip a binary tree
-  What is the underlying data structure for JAVA hashmap? Answer: BST,so
that the keys are sorted.
-  Find the lowest common parent in a binary tree
-  Given a huge file, each line of which is a person’s name. Sort thenames
using a single computer with small memory but large disk space
-  Design a data structure to quickly compute the row sum and column sumof
a sparse matrix  
-  Design a wrapper class for a pointer to make sure this pointerwill
always be deleted even if an exception occurs in the middle

我个人觉得面试machinelearning相关职位前需要熟悉的四大块：
Classification:
Logistic regression
Neural Net (classification/regression)
SVM
Decision tree
Random forest
Bayesian network
Nearest neighbor classification

Regression:
Neural Net regression
Linear regression
Ridge regression (add a regularizer)
Lasso regression
Support Vector Regression
Random forest regression
Partial Least Squares

Clustering:
K-means
EM
. 1point 3 acresMean-shift
Spectral clustering
Hierarchical clustering

Dimension Reduction:
PCA
ICA
CCA
LDA
Isomap
LLE
Neural Network hidden layer

谢谢楼主，我是物理专业的new grad PhD，最近也在刷题和复习ml，加油！

一年前有个波士顿的HR电话说要面试DS方面的，我说了要sponsor，然后再也没联系过我~