Competitive Programming Primer
In this comprehensive guide, we delve into the world of Dynamic Programming with C++. Learn the core principles of Dynamic Programming, explore various algorithmic examples, and understand performance differences through detailed code comparisons. Perfect for developers looking to optimize their coding skills and enhance algorithm efficiency.
Competitive Programming Primer: 100 Preparatory Challenges
Welcome to our Competitive Programming Primer series!
In this comprehensive preparatory course, we’re excited to present 100 carefully curated programming challenges designed to sharpen your skills and prepare you for the intense world of competitive programming.
Competitive programming is not just about coding—it’s about problemsolving, efficiency, and thinking outside the box. These skills are invaluable, whether you’re aiming for:
 Success in programming competitions
 Excelling in technical interviews
 Enhancing your overall software development prowess
Our primer is structured to gradually build your competence, starting from fundamental concepts and progressing to more advanced techniques commonly encountered in competitive programming.
How It Works
Every Friday, we’ll post a set of challenges here. These problems are crafted to:
 Reinforce essential algorithms and data structures
 Improve your time management and problemsolving speed
 Expose you to a variety of problem types you’ll face in real competitions
But we don’t stop there!
The following Monday, we’ll release detailed solutions for each problem in both Python and C++ 20. This duallanguage approach serves to:
 Cater to different language preferences
 Showcase languagespecific optimizations
 Provide a comparative view of problemsolving approaches
What to Expect
Each problem set will include:
 Clear problem statements
 Input/output specifications
 Constraints to consider
 Hints for those who need a nudge in the right direction
Our solutions will feature:
 Wellcommented code
 Explanations of the underlying logic
 Time and space complexity analysis
 Tips for optimization
Are you ready to embark on this journey to competitive programming excellence? Dive into our first set of challenges below, and remember—consistent practice is key to mastering these skills.
Happy coding, and may your algorithms always be efficient! 🖥️💪
First Week’s Challenges

Widget Batch Sorting
A factory produces widgets in batches. Each batch is assigned a number between 2000 and 3200. Batches divisible by 7 are sent to Warehouse A, unless they’re also divisible by 5, in which case they go to Warehouse B. Write a program to list all batch numbers sent to Warehouse A.
Input: None Output: A commaseparated list of integers
Example Output:
2002,2009,2016,2023,2037,2044,2051,2058,2072,2079,2086,2093,2107,2114,2121,2128,2142,2149,2156,2163,2177,2184,2191,2198
Hint: Use a
list
to store the batch numbers and therange()
function for iteration. Thejoin()
method can be used to create the commaseparated output string. 
Bacterial Growth Calculator
A microbiologist is studying bacterial growth. The population doubles every generation. Given the number of generations, calculate the final population if starting with a single bacterium.
Input: An integer $n$ representing the number of generations Output: An integer representing the final population
Example: Input:
8
Output:256
Hint: This is effectively a factorial calculation. Implement a recursive function. Use
int()
to convert input to an integer. 
Student Square Number Reference
A teacher wants to create a quick reference sheet for square numbers. For a given number of students $n$, create a dictionary where the keys are student numbers (1 to $n$) and the values are their numbers squared.
Input: An integer $n$ representing the number of students Output: A dictionary where keys are integers from 1 to $n$, and values are their squares
Example: Input:
5
Output:{1: 1, 2: 4, 3: 9, 4: 16, 5: 25}
Hint: Use a
dict()
to create the dictionary. Afor
loop withrange()
can generate the student number and squared value pairs. 
Daily Sales Data Analyzer
A grocery store manager needs to analyze sales data. Write a program that takes commaseparated prices of items sold in a day, and generates both a list and a tuple of these prices.
Input: A string of commaseparated floatingpoint numbers Output: A list and a tuple containing the input numbers
Example: Input:
23.5,18.9,31.2,15.5,42.8
Output:['23.5', '18.9', '31.2', '15.5', '42.8'] ('23.5', '18.9', '31.2', '15.5', '42.8')
Hint: Use
string.split()
to parse the input. Convert the result directly to alist
and then to atuple
. 
Chatbot Text Processor
Design a simple text processing class for a chatbot. It should have methods to get input from a user and to respond with the input converted to uppercase.
Input: A string from the user Output: The input string converted to uppercase
Example: Input:
Hello, how are you?
Output:HELLO, HOW ARE YOU?
Hint: Use
raw_input()
(orinput()
in Python 3) for getting input. Implement__init__
method to initialize an empty string attribute. 
Water Tank Volume Calculator
An engineer is designing a series of water tanks. The volume $Q$ of each cylindrical tank is given by:
\[Q = \sqrt{\frac{2 * C * D}{H}}\]where $C = 50$ (a flow coefficient) and $H = 30$ (the height of each tank). $D$ is the diameter, which varies for each tank. Write a program to calculate $Q$ for a series of diameters input as a commaseparated sequence.
Input: A string of commaseparated integers representing diameters Output: A commaseparated string of floatingpoint numbers rounded to two decimal places
Example: Input:
100,150,180
Output:18.11,22.16,24.28
Hint: Use
math.sqrt()
for square root. Parse input into alist
and use list comprehension to calculate volumes. 
Simple Voice Recognition
Create a simple voice recognition program that prints “Command Accepted” if it hears “Yes” in any capitalization, otherwise it prints “Command Declined”.
Input: A string representing the voice input Output: Either “Command Accepted” or “Command Declined”
Example 1: Input:
yes
Output:Command Accepted
Example 2: Input:
No
Output:Command Declined
Hint: Use string methods like
lower()
orupper()
to standardize the input before comparison. 
ASCII to UTF8 Converter
A data analyst needs to convert ASCIIencoded data from an old system into UTF8 for modern analysis. Write a program to perform this conversion on a given input string.
Input: An ASCIIencoded string Output: The same string encoded in UTF8
Example: Input:
Hello, world!
Output:Hello, world!
(but encoded in UTF8)Hint: In Python 2, use
unicode()
function with ‘utf8’ encoding. In Python 3, strings are already unicode. 
Savings Growth Calculator
An economist is modeling savings growth. The model is:
\[savings(n)=savings(n−1)+100savings(n) = savings(n1) + 100savings(n)=savings(n−1)+100\]where $n$ is the number of months and $savings(0) = 1000$. Write a program to calculate savings for a given number of months.
Input: An integer $n$ representing the number of months Output: The total savings after $n$ months
Example: Input: 5 Output: 1500
Hint: Implement a recursive function. Use a base case for $n=0$. Convert input to integer using int().

Library Book Checkout System
A local library is implementing a digital system to track book checkouts. Each book has a unique 5digit ID number. Books with ID numbers divisible by 3 are placed on the “Featured” shelf. However, if the ID is also divisible by 4, it goes to the “Classics” section instead. Create a program to help librarians quickly determine where to place a book.
Input: An integer $n$ representing the book ID (10000 ≤ $n$ ≤ 99999) Output: A string: “Featured”, “Classics”, or “Regular”
Examples: Input:
10002
Output:Regular
Input:
10353
Output:Featured
Input:
10512
Output:Classics
Hint: Use the modulo operator
%
to check divisibility. Implement conditional statements to determine the correct category based on the ID number.Extra Challenge: Instead of a single ID, allow the librarian to input a commaseparated list of book IDs and output the category for each book in the same order.
Example for Extra Challenge: Input:
10002,10353,10512
Output:Regular,Featured,Classics
Solutions will be posted on Monday. Stay tuned!