1-Second Prime Showdown

Finding prime numbers is a foundational concept in computer science, deeply tied to cryptography and hardware benchmarking. Today, we're testing not just your math skills, but how well you can optimize code to utilize CPU cycles and memory most efficiently.

1. A Closed Book: No Google, StackOverflow, ChatGPT, Claude, etc. If it feels like cheating, it probably is. The only reference you can use is the offline documentation search at the bottom of this page.
2. B The Defense: To claim the winning title, you must explain exactly how and why your optimization works (similar to the Troubleshooting Workshop). If you can't explain your code, you will be banned from the club forever and expelled from OSU. No pressure though.
3. C Time Limit: Your code must stop executing exactly 1 second after the calculation loop begins (handled by the starter code).
4. D Output: Your script must print the total count of primes found. No hardcoded arrays.
5. E Language: Python 3. Yes, Python is slow. Shut up CS nerd.
6. F Sequentiality: Primes must be computed sequentially. This means you can just jump to 1 billion and start there. First prime computed must be 2.
7. G Final Test: All submissions will be tested on the host's laptop for fairness. The highest valid count wins.

This baseline works, but it's incredibly slow. Copy it into a file named prime.py and run it to see your starting score.

import time

def is_prime(n):
    """A very naive and slow way to check for a prime number."""
    if n <= 1:
        return False
    # Checks every single number up to n
    for i in range(2, n):
        if n % i == 0:
            return False
    return True

def main():
    print("Starting Prime Hunt for exactly 1.0 second...")
    start_time = time.time()
    duration = 1.0

    prime_count = 0
    current_number = 2

    # Run the loop until 1 second has passed
    while (time.time() - start_time) < duration:
        if is_prime(current_number):
            prime_count += 1
        current_number += 1

    print("\n--- TIME'S UP! ---")
    print(f"Total primes found: {prime_count}")
    print(f"Highest number checked: {current_number - 1}")

if __name__ == "__main__":
    main()

The starter code won't win. It relies on brute force. To reach the millions, you need to fundamentally change the way you think about prime numbers. Discuss these concepts with your team, and use them as a springboard to get your development started:

Open your terminal, navigate to your folder, and run:

$ python3 prime.py

What number did it return? Great, make it go higher.

Search this local Python reference by concept, syntax, or optimization keyword. No internet needed.