每日一练 | Data Scientist & Business Analyst & Leetcode 面试题 488

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Nov.

19

Data Application Lab 自2017年6月15日起,每天和你分享讨论一道数据科学(DS)和商业分析(BA)领域常见的面试问题。

自2017年10月4日起,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

388

DS Interview Question

Describe what is the Artificial Neural Network?

BA Interview Question

Write a query in SQL to obtain the names of all the nurses who have ever been on call for room 122.

LeetCode Question

Remove Duplicates from Sorted Array II

Description:

Follow up for “Romove Duplicates”

What if duplicates are allowed at most twice?

Input: [1,1,2,2,2,3,3,3]

Output: [1,1,2,2,3,3]

Day

387

答案揭晓

DS Interview Question & Answer

Tell me the process you will use to perform an A/B Testing.

Answer:

 

1.Collect Data: Look for pages with low conversion rates or high drop-off rates that can be improved.

2.Identify Goals: Your conversion goals are the metrics that you are using to determine whether or not the variation is more successful than the original version.

3.Generate Hypothesis: Make the hypothesis for the plan you think it will improve the webpage

4.Create Variations: Make the desired changes to an element of your website or mobile app experience.

5.Run Experiment: Kick off your experiment and wait for visitors to participate! At this point, visitors to your site or app will be randomly assigned to either the control or variation of your experience. Their interaction with each experience is measured, counted, and compared to determine how each performs.

6.Analyze Results

BA Interview Question & Answer

Write a query in SQL to obtain the name of all those physicians who completed a medical procedure with certification after the date of expiration of their certificate, their position, procedure they have done, date of procedure, name of the patient on which the procedure had been applied and the date when the certification expired.

Answer:

SELECT p.name AS “Physician”,       p.position AS “Position”,       pr.name AS “Procedure”,       u.date AS “Date of Procedure”,       pt.name AS “Patient”,       t.certificationexpires AS “Expiry Date of Certificate”FROM physician p,     undergoes u,     patient pt,     PROCEDURE pr,               trained_in tWHERE u.patient = pt.ssn  AND u.procedure = pr.code  AND u.physician = p.employeeid  AND Pr.code = t.treatment  AND P.employeeid = t.physician  AND u.Date > t.certificationexpires;

https://www.w3resource.com/sql-exercises/hospital-database-exercise/sql-exercise-hospital-database-34.php

LeetCode Question & Answer

Remove Duplicates from Sorted List

Description:

Given a sorted linked list, delete all duplicates such that each element appear only once

Input: 1 → 1 → 2

Output: 1 → 2

Tips: 

基础的链表去重题目, 需要用到dummy node来简化特殊情况,省去很多条件判断,每次遍历一个node,需要注意指针的赋值

Code:  

时间复杂度:O(n)

空间复杂度:O(1)


往期精彩回顾

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兄dei,你想做数据分析?那你不仅要有想象力还得有创造力。

如何打造不被HR忽略的完美简历,一篇值得你拿出简历认真研读的高能干货

在面试官问你,“Any Questions for Us?”的时候,这10个问题可以助你锁定offer!


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