I was wondering if there was a simple way to exit a program in case the time limit would be exceeded. Often times I might accidentally created an infinite loop, miscalculate time complexity, etc. and my computer freezes up where I have to reboot. Seems as though there should be easy solutions to this, but I couldn’t find any. Thanks in advance!

I was curious what the consensus was on the merits of practicing on past contests as opposed to simply solving problems by rating/tag. If I had a block of time (2-3 hours) to dedicate to setting up contest-like conditions, would doing virtual contests/upsolving be a stronger use of time contrasted to grinding out problems?