每日一练 | Data Scientist & Business Analyst & Leetcode 面试题 317

大数据应用 · 公众号 · 大数据 · 2018-03-21 09:54

正文

自2017年6月15日起，数据应用学院与你一起温习数据科学（DS）和商业分析（BA）领域常见的面试问题。从2017年10月4号起，每天再为大家分享一道Leetcode算法题。

希望积极寻求相关领域工作的你每天关注我们的问题并且与我们一起思考，我们将会在第二天给出答案。

Day 217

DS Interview Questions

What is latent semantic indexing? What is it used for? What are the specific limitations of the method?

BA Interview Questions

SQL: Query all columns for all American cities in CITY with populations larger than 100000. The CountryCode for America is USA.

The CITY table is described as follows:

LeetCode Questions

Description:

Given a linked list, swap every two adjacent nodes and return its head.

Input: 1->2->3->4

Output: 2->1->4->3

Assumptions:

Your algorithm should use only constant space.

You may not modify the values in the list, only nodes itself can be changed.

欲知答案如何？请见下期分解！

Day 216 答案揭晓

DS Interview Questions

What do you understand by Bias Variance trade off ?

The error emerging from any model can be broken down into three components mathematically. Following are these component :

Bias error is useful to quantify how much on an average are the predicted values different from the actual value. A high bias error means we have a under-performing model which keeps on missing important trends.

Variance on the other side quantifies how are the prediction made on same observation different from each other. A high variance model will over-fit on your training population and perform badly on any observation beyond training.

BA Interview Questions

What is Engaged and Not Engaged in digital marketing?

Engaged vs not engaged will be a unique threshold for each individual business. In this metric, the engagement threshold can be defined as Average Time on Site or Pages per Visit. Both measures provide a strong indication for the quality of a visit. Digital marketers may also want to track a metric like goal completion rate.