Warnings

• Time and Space: Submitted programs must be reasonably efficient; limits on execution time, elapsed time, and memory usage are in effect. Exceeding any of the preset limits will cause an immediate fatal error which will be reported to you.
  
  
• Illegal Operations: Programs must not attempt to open any files, or sockets or pipes, allocate shared memory, or in general do anything that could enable communication with another process or anything else. The standard input and output streams will be already open, and they are all you will need and all you will be permitted to use.
  A list of permitted functions will be posted at some point in the near-ish future. Until then you will have to make sensible assumptions about what is permitted. As a general rule, any function that attempts to open a file, pipe, or socket, or creates a process, or modifies actions taken on receiving a signal, will kill your program.
  
  
• Microsoft: Be warned that the Microsoft compiler is incorrect. The judge uses a correct compiler. You must follow the ISO C++ standard for the scope of control variables declared inside a for statement.
  The following is correct, but rejected by the microsoft compiler:
          { for (int i=0; i<10; i+=1) cout<<i;
            for (int i=10; i>0; i-=1) cout<<i; }
  The following is incorrect, but accepted by the microsoft compiler:
          { for (int i=0; i<10; i+=1) cout<<i;
            for (i=10; i>0; i-=1) cout<<i; }