OJ是Online Judge系统的简称，用来在线检测程序源代码的正确性。

Accepted (AC)  : OK! Your program is correct! Presentation Error (PE) : Output Format Error. Your output format is not exactly the same as the judge's output, although your answer to the problem is correct. Check your output for spaces, blank lines, etc. against the problem output specification. Wrong Answer (WA) : Correct solution not reached for the inputs. The inputs and outputs that we use to test the programs are not public. Some problems with special judge may not reply "Presentation Error", replaced by "Wrong Answer". Runtime Error (RE) : Your program failed during the execution (segmentation fault, floating point exception...). The exact cause is reported except Java. Time Limit Exceeded (TLE) : Your program tried to run with too much CPU time. Memory Limit Exceeded (MLE) : Your program tried to use more memory than the judge default settings. Output Limit Exceeded (OLE): Your program tried to write too much. This usually occurs if it goes into an infinite loop. The output limit is usually 256K, 512K, or 1M bytes. Compilation Error (CE) : The compiler (gcc/g++/gpc/fpc/javac) could not compile your program. Of course, warning messages are not error messages. Click the link at the judge reply to see the actual error message. Restricted Function (RF): Your program tried to call restricted functions. For example, maybe you have tried to open a file which is forbidden on OJ. It may also caused by Runtime Error (e.g. maybe a pointer point to wrong funtion), just consider it as Runtime Error in this situation. Internal Error (IE): The Judge system cause an internal error, please submit it later.