Read a line of input faster than fgets?
Use fgets_unlocked(), but read carefully what it does first
Get the data with fgetc() or fgetc_unlocked() instead of fgets(). With fgets(), your data is copied into memory twice, first by the C runtime library from a file to an internal buffer (stream I/O is buffered), then from that internal buffer to an array in your program
You don't say which platform you are on, but if it is UNIX-like, then you may want to try the read() system call, which does not perform the extra layer of buffering that fgets() et al do. This may speed things up slightly, on the other hand it may well slow things down - the only way to find out is to try it and see.