Do you want to run this Docker container locally?

 docker run -d --name numberizer --restart unless-stopped -p 9007:80 joshbeck2024/numberizer:latest

Short Summary

Key idea (short version)

1e99 becomes infinity (INF) in PHP.

When INF is converted to an integer, PHP turns it into 0.

• The code detects this mismatch and deliberately sets $sum = -1.

What’s happening:

• Scientific notation → float
• Float overflow → INF
• INF → intval() → 0
• Logic interprets this as an error → sets -1

Solution:

curl -X POST '<http://sem2ctf.icsi.cyber:9007/>' -d 'numbers[]=1e99&numbers[]=1e99&numbers[]=1e99&numbers[]=1e99&numbers[]=1e99'

Supplying an extremely large number will cause an integer overflow, resulting in a negative value.

• A workaround was to use scientific notation, such as 1e99, which represents 10^99.
• This notation is valid under the length constraint but still evaluates to a very large number, causing an overflow when summed.

Here is the application code with concise comments: