Online judges allow us to submit problems multiple times. But I wonder if in real programming contest(IOI, ACM…), are we allowed to submit problems multiple time, if yes do we get penalized?
You can submit solutions as many times as you like. However, there are penalties for wrong submissions (wrong answers, time limit exceeded, run time error) for ACM-ICPC, and there is no penalty for the IOI contest. For other contests, there could be other contest specific rules.
For example, for ranking and penalties on CodeChef contests refer to this thread: https://discuss.codechef.com/questions/53952/types-of-ranklists-on-codechef
Both IOI and ACM-ICPC but you get penalties on ACM-ICPC if you submit problem multiple time.
Ya you can submit. In code chef long challenge there is a limit of 200/500 submission per question during contest. Short contest , acm icpc and ioi allows us to submit multiple times. But penalty is imposed for wrong submission in codechef cook offs and acm icpc. No penalty in IOI.
In lunchtime also unlimited times