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Dell Sonicwall Interview Questions

Dell Sonicwall Interview Guides

Data Structures & Algorithms

Given two sorted lists, write a function to merge them into one sorted list.

Merge Sorted Lists

Write a function to create a single dataframe with complete addresses in the format of street, city, state, zip code.

Complete Addresses

Write a function n_frequent_words that returns the top N frequent words and their frequencies, and state its run-time

Get Top N Frequent Words

Given an integer N, write a function that returns all of the prime numbers up to N

Prime to N

Write a function is_subsequence to find out if string1 is a subsequence of string2

String Subsequence

Machine Learning

How would we build a model to detect fraud and text customers to approve or deny fraudulent transactions

Bank Fraud Model

What are some machine learning methods for building this system

FAQ Matching

Would a logistic model remain valid if one variable had decimal points accidentally removed, and how would you fix it

Variable Error

Design a function to detect anomalies in univariate and bivariate data

Variate Anomalies

Credit Card Fraud Model

Select the 2nd highest salary in the engineering department

2nd Highest Salary

Write a query to get the largest salary of any employee by department

Largest Salary by Department

Write a SQL query to count transactions filtered by several criterias.

Count Transactions

Write a query to repeat each int_numbers value by its own value in the output

Sequentially Fill in Integers

Compute the cumulative sales for each product.

Cumulative Sales By Product

Behavioral

Describing a data project and its challenges

Hurdles In Data Projects

How to present complex data insights with clarity and adaptability tailored to a specific audience

Presentations and Insights

How would you negotiate and resolve disagreements when a client rejects your proposed solution?

Client Solution Pushback

How would you answer when an Interviewer asks why you applied to their company?

Why Do You Want to Work With Us

What do you tell an interviewer when they ask you what your strengths and weaknesses are?

Your Strengths and Weaknesses

Data Modeling

Design a database schema for a Tinder-style dating app and discuss needed optimizations

Swiping App Design

Design the database schema to support user profiles and restaurant reviews with text and images

Yelp-like System

Design a database for a ride-sharing app.

Ride-Sharing App Schema

Design the backend and data model for a notification system

Reddit-like Notifications

Write a SQL query to select the 2nd highest salary in the engineering department.

Note: If more than one person shares the highest salary, the query should select the next highest salary.

Example:

Input:

<code>employees</code> table

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>first_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>last_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>department_id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<code>departments</code> table

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>
Output:

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>

Given two sorted lists, write a function to merge them into one sorted list.

Bonus: What’s the time complexity?

Example:

Input:

<pre tabindex="0" class="chroma"><code>list1 = [1,2,5]
list2 = [2,4,6]
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def merge_list(list1,list2) -&gt; [1,2,2,4,5,6]
</code></pre>

You have two sorted lists, one with m elements and one with n elements. What would be the time complexity of merging the two lists via merge sort?

You have two sorted lists, one with m elements and one with n elements. What would be the time complexity of merging the two lists via merge sort? 

Merging Lists Complexity

Let’s say that you work at a bank that wants to build a model to detect fraud on the platform.

The bank wants to implement a text messaging service in addition that will text customers when the model detects a fraudulent transaction in order for the customer to approve or deny the transaction with a text response.

How would we build this model?

Let’s say that you work at a bank that wants to build a model to detect fraud on the platform.

The bank wants to implement a text messaging service that will text customers when the model detects a fraudulent transaction in order for the customer to approve or deny the transaction with a text response.

Which statement is true?

Let's say that you work at a bank that wants to build a model to detect fraud on the platform.

The bank wants to implement a text messaging service that will text customers when the model detects a fraudulent transaction in order for the customer to approve or deny the transaction with a text response.

Which statement is true?

Given an integer <code>N</code>, write a function that returns a list of all of the prime numbers up to <code>N</code>.

Note: Return an empty list there are no prime numbers less than or equal to <code>N</code>.

Example:

Input:

<pre tabindex="0" class="chroma"><code>N = 3
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def prime_numbers(N) -&gt; [2,3]
</code></pre>

Given a table called <code>employees</code>, get the largest salary of any employee by department

Example:

Input:

<code>employees</code> table

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>department</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
Output:

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>department</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>largest_salary</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>

How would you explain what a p-value is to someone who is not technical?

What does a p-value in a statistical test represent?

What does a p-value in a statistical test represent?

P-value to a Layman I

In a statistical test, how does a low p-value (less than 0.05) influence our decision about the null hypothesis?

In a statistical test, how does a low p-value (less than 0.05) influence our decision about the null hypothesis?

P-value to a Layman II

Explain what a p-value is to someone who is not technical

P-value to a Layman

Statistics

Tell me about a data project that didn’t go the way you expected. What did you set out to do, what surprised you, and how did you handle it?

You’re given two dataframes. One contains information about addresses and the other contains relationships between various cities and states:

Example:

<code>df_addresses</code>

<table>
<thead>
<tr>
<th>address</th>
</tr>
</thead>

<tbody>
<tr>
<td>4860 Sunset Boulevard, San Francisco, 94105</td>
</tr>

<tr>
<td>3055 Paradise Lane, Salt Lake City, 84103</td>
</tr>

<tr>
<td>682 Main Street, Detroit, 48204</td>
</tr>

<tr>
<td>9001 Cascade Road, Kansas City, 64102</td>
</tr>

<tr>
<td>5853 Leon Street, Tampa, 33605</td>
</tr>
</tbody>
</table>
<code>df_cities</code>

<table>
<thead>
<tr>
<th>city</th>
<th>state</th>
</tr>
</thead>

<tbody>
<tr>
<td>Salt Lake City</td>
<td>Utah</td>
</tr>

<tr>
<td>Kansas City</td>
<td>Missouri</td>
</tr>

<tr>
<td>Detroit</td>
<td>Michigan</td>
</tr>

<tr>
<td>Tampa</td>
<td>Florida</td>
</tr>

<tr>
<td>San Francisco</td>
<td>California</td>
</tr>
</tbody>
</table>
Write a function <code>complete_address</code> to create a single dataframe with complete addresses in the format of street, city, state, zip code.

Input:

<pre tabindex="0" class="chroma"><code>import pandas as pd

addresses = {&#34;address&#34;: [&#34;4860 Sunset Boulevard, San Francisco, 94105&#34;, &#34;3055 Paradise Lane, Salt Lake City, 84103&#34;, &#34;682 Main Street, Detroit, 48204&#34;, &#34;9001 Cascade Road, Kansas City, 64102&#34;, &#34;5853 Leon Street, Tampa, 33605&#34;]}

cities = {&#34;city&#34;: [&#34;Salt Lake City&#34;, &#34;Kansas City&#34;, &#34;Detroit&#34;, &#34;Tampa&#34;, &#34;San Francisco&#34;], &#34;state&#34;: [&#34;Utah&#34;, &#34;Missouri&#34;, &#34;Michigan&#34;, &#34;Florida&#34;, &#34;California&#34;]}

df_addresses = pd.DataFrame(addresses)
df_cities = pd.DataFrame(cities)
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def complete_address(df_addresses,df_cities) -&gt;
</code></pre>

<table>
<thead>
<tr>
<th>address</th>
</tr>
</thead>

<tbody>
<tr>
<td>4860 Sunset Boulevard, San Francisco, California, 94105</td>
</tr>

<tr>
<td>3055 Paradise Lane, Salt Lake City, Utah, 84103</td>
</tr>

<tr>
<td>682 Main Street, Detroit, Michigan, 48204</td>
</tr>

<tr>
<td>9001 Cascade Road, Kansas City, Missouri, 64102</td>
</tr>

<tr>
<td>5853 Leon Street, Tampa, Florida, 33605</td>
</tr>
</tbody>
</table>

Assume you have a logistic model that is heavily weighted on one variable and that one variable has sample data like 50.00, 100.00, 40.00, etc….

Next let’s assume that there was a data quality issue with that variable and an unknown number of values removed the decimal point. For example 100.00 turned into 10000.

Would the model still be valid? Why or why not? How would you fix the model?

In predicting Airbnb booking prices with a dataset containing thousands of diverse features, which regression model could potentially perform better?

In predicting Airbnb booking prices with a dataset containing thousands of diverse features, which regression model could potentially perform better?

You are given an N-dimensional array (a nested list) and your task is to convert it into a 1D array. The N-dimensional array can have any number of nested lists and each nested list can contain any number of elements. The elements in the nested lists are integers. Write a function that takes an N-dimensional array as input and returns a 1D array.

Example 1:

Input:

<pre tabindex="0" class="chroma"><code>array = [1, [2, 3], [4, [5, 6]], 7]
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>flatten_array(array) -&gt; [1, 2, 3, 4, 5, 6, 7]
</code></pre>

Example 2:

Input:

<pre tabindex="0" class="chroma"><code>array = [[1, 2], [3, 4], [5, 6]]
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>flatten_array(array) -&gt; [1, 2, 3, 4, 5, 6]
</code></pre>

The task is to write a function that takes an N-dimensional array (nested lists) as input and returns a 1D array. The N-dimensional array can have any number of nested lists and each nested list can contain any number of elements.

Flatten N-Dimensional Array to 1D Array

<ol>
<li>Given an example paragraph string and an integer <code>N</code>, write a function <code>n_frequent_words</code> that returns the top <code>N</code> frequent words in the posting and the frequencies for each word.</li>

<li>What’s the function run-time?</li>
</ol>

Example:

Input:

<pre tabindex="0" class="chroma"><code>posting = &#34;&#34;&#34;
Herbal sauna uses the healing properties of herbs in combination with distilled water. 
The water evaporates and distributes the effect of the herbs throughout the room. 
A visit to the herbal sauna can cause real miracles, especially for colds. 
&#34;&#34;&#34; 
n = 3
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>n_frequent_words(posting,N) = [
 (&#39;the&#39;, 6), 
 (&#39;herbal&#39;, 2), 
 (&#39;sauna&#39;, 2),
]
</code></pre>

Given two strings, <code>string1</code> and <code>string2</code>, write a function <code>is_subsequence</code> to find out if <code>string1</code> is a subsequence of <code>string2</code>.

Bonus: A subsequence is a sequence that can be derived from another sequence by deleting some elements without changing the order of the remaining elements.

Example:

Input:

<pre tabindex="0" class="chroma"><code>string1 = &#39;abc&#39;
string2 = &#39;asbsc&#39;
string3 = &#39;acedb&#39;

is_subsequence(string1, string2) -&gt; True
is_subsequence(string1, string3) -&gt; False
</code></pre>

Blizzard Entertainment operates a global network of games and services, each generating massive volumes of real-time gameplay and infrastructure events, everything from player actions in Overwatch to server status updates for World of Warcraft. You are tasked with building a centralized system to reliably ingest, process, and distribute these events across the company for analytics, live operations, and player-facing features.

How would you architect the data ingestion and processing pipeline for this event system?

Design a scalable event data pipeline for real-time, multi-application ingestion and processing.

Centralized Event Ingestion

Data Pipelines

You have been given a table <code>tbl_numbers</code> with only one column: <code>int_numbers</code>. It can have one integer number value per row in a sequential manner.

Write a query to return the number repeated by one times its own value.

For example, the integer number 5 would appear five times in the output (1 times 5).

Example:

Input:

<code>tbl_numbers</code> table

<table>
<thead>
<tr>
<th>int_numbers</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>1</code></td>
</tr>

<tr>
<td><code>2</code></td>
</tr>

<tr>
<td><code>3</code></td>
</tr>

<tr>
<td><code>4</code></td>
</tr>
</tbody>
</table>
Output:

<table>
<thead>
<tr>
<th>seq_numbers</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>1</code></td>
</tr>

<tr>
<td><code>2</code></td>
</tr>

<tr>
<td><code>2</code></td>
</tr>

<tr>
<td><code>3</code></td>
</tr>

<tr>
<td><code>3</code></td>
</tr>

<tr>
<td><code>3</code></td>
</tr>

<tr>
<td><code>4</code></td>
</tr>

<tr>
<td><code>4</code></td>
</tr>

<tr>
<td><code>4</code></td>
</tr>

<tr>
<td><code>4</code></td>
</tr>
</tbody>
</table>

Given a <code>ListNode</code> representing the head of a linked list, write a function <code>is_cyclic</code> which returns <code>True</code> if a linked list is cyclic and <code>False</code> if it is not. A linked list is cyclic when there is no tail to the linked list, and the supposed tail is attached to another node inside the list itself, creating a cycle.

A <code>ListNode</code> is defined as:

<pre tabindex="0" class="chroma"><code>class ListNode:
	value: ListNode = None
 next: ListNode = None
</code></pre>

Example:

Input:

<img src="/s3/questions/1a65651d-a483-4481-b073-2738d65ab9d7.png" alt="image"/>

Output:

<pre tabindex="0" class="chroma"><code>def is_cyclic(head) -&gt; True
</code></pre>

Cyclic Detection

Write a Python function called <code>group_anagrams</code> that takes a list of strings as input and returns a list of lists, where each inner list contains a group of anagrams that were present in the input list.

An anagram is a word or phrase formed by rearranging the letters of a different word or phrase, using all the original letters exactly once.

Note: Each of the inner lists should be ordered alphabetically and contain no duplicate values

<h3>Example:</h3>

Input:

<pre tabindex="0" class="chroma"><code>words = [&#34;eat&#34;, &#34;tea&#34;, &#34;tan&#34;, &#34;ate&#34;, &#34;nat&#34;, &#34;bat&#34;]
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>[ 
 [&#34;nat&#34;,&#34;tan&#34;],
 [&#34;ate&#34;,&#34;eat&#34;, &#34;tea&#34;],
 [&#34;bat&#34;]
]
</code></pre>

Explanation:

In the example, the words “eat”, “tea”, and “ate” are anagrams of each other, as are the words “tan” and “nat”. The word “bat” does not have any anagrams in the input list, and therefore is listed on its own. The function then groups the anagrams together and returns a list of lists representing these groups.

Each of the lists representing a group of anagrams is sorted in alphabetical order.

Identify the groups of anagrams in a list of words

Groups of Anagrams

Let’s say that we want to build a chatbot system for frequently asked questions. Whenever a user writes a question, we want to return the closest answer from a list of FAQs.

What are some machine learning methods for building this system?

Let’s say you’re given all the different marketing channels along with their respective marketing costs at a company called Mode, that sells B2B analytics dashboards.

What metrics would you use to determine the value of each marketing channel?

When determining the value of each marketing channel for the company Mode, which metric is considered the key metric?

When determining the value of each marketing channel for the company Mode, which metric is considered the key metric?

Marketing Channel Metrics

What metrics would you use to determine the value of each marketing channel?

Analytics

Write a Python function called <code>longest_increasing_subsequence</code> that takes a list of integers as input and returns as output the length of the longest increasing subsequence in the list.

Note: An increasing subsequence is a subset of a list where the elements are in strictly increasing order. The subsequence does not have to be contiguous or unique.

<h3>Example:</h3>

Input:

<pre tabindex="0" class="chroma"><code>nums = [10, 9, 2, 5, 3, 3, 7, 101, 18]
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>4
</code></pre>

Explanation:

The longest increasing subsequence is <code>[2, 3, 7, 101]</code>, for a total length of 4.

Find the longest increasing subsequence in a list of integers.

Longest Increasing Subsequence

Given a list of strings, write a function, <code>sorting</code> from scratch to sort the list in ascending alphabetical order.

Notes:
- Do NOT use the built-in <code>sorted</code> function
- Return the new sorted list, rather than modifying the list in-place

Bonus: Have your solution be \(O(n log(n))\).

Example:

Input:

<pre tabindex="0" class="chroma"><code>array = [&#34;apple&#34;, &#34;cat&#34;, &#34;banana&#34;, &#34;zoo&#34;, &#34;football&#34;]
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def sorting(array) -&gt; [&#34;apple&#34;, &#34;banana&#34;, &#34;cat&#34;, &#34;football&#34;, &#34;zoo&#34;]
</code></pre>

Write a function `sorting` from scratch to sort a list of strings in ascending alphabetical order

Sort Strings

Given a list of strings, write a function that returns their longest common prefix. For example, if you were given the strings <code>&#34;flowers&#34;</code>, <code>&#34;flow&#34;</code>, and <code>&#34;flight&#34;</code>, your function should return the string <code>&#34;fl&#34;</code>.

If the list of strings has no common prefix, return an empty string.

Example 1:

Input:

<pre tabindex="0" class="chroma"><code>strings = [&#34;flowers&#34;, &#34;flow&#34;, &#34;flight&#34;] 
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>&#34;fl&#34;
</code></pre>

Example 2:

Input:

<pre tabindex="0" class="chroma"><code>strings = [&#34;showboat&#34;, &#34;showcase&#34;, &#34;shower&#34;]
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>&#34;show&#34;
</code></pre>

Given a list of strings, write a function that returns the longest common prefix

Common Prefix

Given a list of integers, identify all the duplicate values in the list. Assume that the list can contain both positive and negative numbers, and the order of the list does not matter. A number is considered a duplicate if it appears more than once in the list. Return a list of the duplicate numbers.

Example 1:

Input:

<pre tabindex="0" class="chroma"><code>nums = [1, 2, 3, 1, 2, 3]
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>find_duplicates(nums) -&gt; [1, 2, 3]
</code></pre>

The numbers 1, 2, and 3 all appear more than once in the list, so they are considered duplicates.

Example 2:

Input:

<pre tabindex="0" class="chroma"><code>nums = [1, -1, 2, 3, 3, -1]
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>find_duplicates(nums) -&gt; [-1, 3]
</code></pre>

The numbers -1 and 3 both appear more than once in the list, so they are considered duplicates. Note that the order of the output does not matter.

Example 3:

Input:

<pre tabindex="0" class="chroma"><code>nums = [1, 2, 3, 4, 5]
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>find_duplicates(nums) -&gt; []
</code></pre>

None of the numbers in the list appear more than once, so there are no duplicates.

This problem involves identifying duplicate numbers in a list of integers. The function should return a list of the duplicate numbers.

Find Duplicate Numbers in a List

Given two strings, write a function to return <code>True</code> if the strings are anagrams of each other and <code>False</code> if they are not.

Note: A word is not an anagram of itself.

Example 1:

Input:

<pre tabindex="0" class="chroma"><code>string_1 = &#34;listen&#34;
string_2 = &#34;silent&#34;
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>True
</code></pre>

Example 2:

Input:

<pre tabindex="0" class="chroma"><code>string_1 = &#34;banana&#34;
string_2 = &#34;bandana&#34;
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>False
</code></pre>

Write a function to return True if two strings are anagrams of each other and False if they are not

Valid Anagram

Say you are given a text document in the form of a string with the following sentences:

Example:

Input:

<pre tabindex="0" class="chroma"><code>document = &#34;I have a nice car with a nice tires&#34;
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>
{
&#34;I&#34;:0.11,
&#34;have&#34;:0.11,
&#34;a&#34;:0.22,
&#34;nice&#34;:0.22,
&#34;car&#34;: 0.11,
&#34;with&#34;:0.11,
&#34;tires&#34;:0.11
}
</code></pre>

Write a program in python to determine the TF (<code>term_frequency</code>) values for each term of this document.

Note: Round the term frequency to 2 decimal points.

Write a program in python to determine the TF values for each term of a document

Term Frequency

Given an array and a target integer, write a function <code>sum_pair_indices</code> that returns the indices of two integers in the array that add up to the target integer. If not found, just return an empty list.

Note: Can you do it on \(O(n)\) time?

Note: Even though there could be many solutions, only one needs to be returned.

Example 1:

Input:

<pre tabindex="0" class="chroma"><code>array = [1 2 3 4] 
target = 5 
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def sum_pair_indices(array, target) -&gt; [0 3] or [1 2]
</code></pre>

Example 2:

Input:

<pre tabindex="0" class="chroma"><code>array = [3]
target = 6 
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>Do NOT return [0 0] as you can&#39;t use an index twice.
</code></pre>

Given an array and a target integer, write a function that returns the indices of two integers in the array that add up to the target integer.

Target Indices

Given the head of a singly linked list represented as a <code>ListNode</code>, and two zero-indexed positions <code>x</code> and <code>y</code>, write a function <code>swap_node</code> which swaps the positions of nodes <code>x</code> and <code>y</code> and returns the new head. Note that you cannot simply swap the values of these nodes, as these nodes do not have values. Instead, you must swap these two using pointer manipulation (i.e., modifying the <code>next</code> references of the involved nodes inside the list).

A <code>ListNode</code> is defined as:

<pre tabindex="0" class="chroma"><code>class ListNode:
 next: ListNode = None
</code></pre>

Example:

Input:

<pre tabindex="0" class="chroma"><code>linked_list = ListNode(0x01) -&gt; ListNode(0x02) -&gt; ListNode(0x03) 
# Here, imagine that &#39;0x0_&#39; refer to their memory locations.
head = 0x01
x = 1
y = 2
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def swap_node(head, x, y) -&gt; ListNode(0x01) -&gt; ListNode(0x03) -&gt; ListNode(0x02)
</code></pre>

Swapping Nodes

You are working with the sales team of an e-commerce store to analyze their monthly performance.

They give you the <code>sales</code> table that tracks every purchase made on the store. The table contains the columns <code>id</code> (purchase id), <code>product_id</code>, <code>date</code> (purchase date), and <code>price</code>.

Write a SQL query to compute the cumulative sum of sales for each product, sorted by product_id and date.

Note: The cumulative sum for a product on a given date is the sum of the price of all purchases of the product that happened on that date and on all previous dates.

<h3>Example:</h3>

Input:

<code>sales</code> table

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td>id</td>
<td>INTEGER</td>
</tr>

<tr>
<td>product_id</td>
<td>INTEGER</td>
</tr>

<tr>
<td>date</td>
<td>DATE</td>
</tr>

<tr>
<td>price</td>
<td>FLOAT</td>
</tr>
</tbody>
</table>
Output:

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td>product_id</td>
<td>INTEGER</td>
</tr>

<tr>
<td>date</td>
<td>DATE</td>
</tr>

<tr>
<td>cumulative_sum</td>
<td>FLOAT</td>
</tr>
</tbody>
</table>

Design a database to represent a Tinder style dating app. 

What does the schema look like and what are some optimizations that you think we might need?

Let’s say you are making a swiping app, similar to Tinder.

What would be the most efficient way (in terms of retrieval time) to store which users have swiped on each other on a database backend?

Let's say you are making a swiping app, similar to Tinder.

What would be the most efficient way (in terms of retrieval time) to store which users have swiped on each other on a database backend?

Swipes Database Design

Given an integer <code>n</code>, return the number of trailing zeroes in <code>n!</code>.

Note that <code>n! = n * (n - 1) * (n - 2) * ... * 3 * 2 * 1</code>.

<h3>Example 1</h3>

Input:

<pre tabindex="0" class="chroma"><code>n = 5
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def trailingZeroes(n) -&gt; 1
</code></pre>

Explanation:

<pre><code>5! = 120, one trailing zero.
</code></pre>

<h3>Example 2</h3>

Input:

<pre tabindex="0" class="chroma"><code>n = 10
</code></pre>

Output:

<pre tabindex="0" class="chroma"><code>def trailingZeroes(n) -&gt; 2
</code></pre>

Explanation:

<pre><code>10! = 3,628,800 -&gt; two trailing zero.
</code></pre>

<h3>Constraints:</h3>

<ul>
<li><code>0 &lt;= n &lt;= 10^4</code></li>
</ul>

Return the number of trailing zeroes in n factorial

Factorial Trailing Zeroes

Find all sets of 3 indexes of an array so that the three indexed elements add up to 0.

Note: You may assume the input array is sorted in ascending order.

<h3>Example</h3>

For example, if the input array is:

<pre tabindex="0" class="chroma"><code>array = [-2, -1, 1, 1, 3]
</code></pre>

The result should be:

<pre tabindex="0" class="chroma"><code>result = [{0,1,2}, {2,3,4}]
</code></pre>

Find all sets of 3 indexes whose elements add up to 0.

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