Hello guys, I am studying graphs and I have the following questions:

If I have an undirected and weighted graph, if the costs of each arc increase by 1:

• Does the minimum spanning tree change?
• Do the shortest paths change from vertex $$$v$$$ to others?

Thanks in advance!

Hello, since the end of 2017 I am working in an online judge for my university. The judge is directed to a basic programming course in Python where each semester about 1200 students take the course. The judge was launched 8 months ago and today we have 1542 registered students.

The next step that I would like to give is to give the possibility of creating contests. Currently the judge only has problems that I raise periodically.

I passed a database course, but I need more specific guidance. For example, the scoreboard model. If the contest will be saved in the database I would like the access to be fast to access any scoreboard. I have an idea and it consists of saving each scoreboard in a new table for the database, but I do not know if it is consistent over time.

The online judge is developed using pure php and mysql. The database is relational.

What do you think? Thank you!

Hi, I'm currently working on a project using PHP to develop a judge where my colleagues can send solutions to exercises that are typically from a basic programming course. All solutions must be written in python.

The code is executed in exec() and then the user's output is stored in a .txt file. Later the system reads that file and compares it with a .txt file that has the correct outputs.

The problem is that I can not know when TLE occurs. When a user sends a python file with an infinite buble for example, the web page hangs.

If you have some tip or similar experience I would appreciate it very much.