Running code and reading errors

How results, compile errors and runtime errors are shown, and how output is compared.

Reading a run

After a run, the Test Result tab shows:

an overall verdict, Accepted or Wrong Answer, with how many cases passed (for example 2/3 passed),
a pill for each case (Case 1, Case 2…) with a tick or a cross,
for the case you open: its Input, your Output ("(no output)" if empty), the Expected output for failed sample cases, and the time (ms) and memory (KB) used.

You see	What it means
Compile error	Your code didn't compile. The message shows where. Fix it and run again.
Runtime error	Your program crashed or wrote to the error stream. The message is shown.
A status such as Time Limit Exceeded	It took longer than the question's limit. The page shows "Time limit N ms".
Note	Extra information from the runner.

Spaces and blank lines at the end are ignored. Everything else must match exactly.
Some number questions have a tolerance: every number you print only has to be within a small percentage of the expected value, so rounding differences don't fail you. The page says so, for example "Numbers in your output pass within 2% of the expected value." The count of lines and numbers must still match.

Sample tests are the ones you can see. Hidden tests run only when your answer is graded, and their input and expected output are never shown.