每日一练 | Data Scientist Business Analyst Leetcode 面试题 1205

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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。

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DS Interview Question

Explain bagging.

BA Interview Question

Write a query in SQL to count number of unique patients who got an appointment for examination room C

LeetCode Question

Pascal’s Triangle II

Description:

Given an index k, return the kth row of the Pascal’s triangle.

Input: 3

Output: [1,3,3,1]

DSInterview Question & Answer

How can you choose a classifier based on training set size?

If training set is small, high bias / low variance models (e.g. Naive Bayes) tend to perform better because they are less likely to be overfit.

If training set is large, low bias / high variance models (e.g. Logistic Regression) tend to perform better because they can reflect more complex relationships.

BA Interview Question & Answer

Write a query in SQL to find the name of the patients and the number of physicians they have taken appointment.

Answer:

SELECT p.name "Patient",
count(a.patient) "Appointment for No. of Physicians"
FROM appointment a

JOIN patient p ON a.patient=p.ssn
GROUP BY p.name
HAVING count(a.patient)>=1;

LeetCode Question & Answer

Pascal’s Triangle

Description:

Given numRows, generate the first numRows of Pascal’s triangle.

Input: 5

Output:

[

[1],

[1,1],

[1,2,1],

[1,3,3,1],

[1,4,6,4,1]

]

Solution:

模拟题，根据图上的规律来进行循环

注意防止数组越界

Code:

Time Complexity: O(n^2)

Space Complexity: O(1)