-1.00 execution time in tiebreaker question

When do i get a execution time of -1.00 ? What does it mean ?
The verdict is still the wa but what does -1 signify in execution time?


I think it has got nothing to do with time as such,it just means Wrong answer.
(I actually got the same verdict and when i rectified a small bug it gave correct answer.)

Make very very sure you’re flushing all you I/O buffers. I had this problem in Python and I fixed it by doing


after every time I print a response.

I was facing the same problem in Snackdown’s elimination round yesterday even after using fflush(stdout) after answering each query.
Problem link - https://www.codechef.com/SNCKEL16/problems/SEGSUMQ
What can be the possible reasons for -1 execution time?