A collection of completed Java challenges with a range of difficulties.
Challenges are scored by execution speed and memory usage; you might notice I've done some very unorthodox stuff to boost performance in a couple places. Naming conventions are all over the place as they are just enough for me to keep track of what's going on. I didn't originally intend for this code to be public.
Good example would be my substitute for Integer.parseInt(..)
public static int parseInt( final String s )
{
int num = 0;
int sign = -1;
final int len = s.length( );
final char ch = s.charAt( 0 );
if ( ch == '-' )
sign = 1;
else
num = '0' - ch;
int i = 1;
while ( i < len )
num = num*10 + '0' - s.charAt( i++ );
return sign * num;
} At the time I was completing these challenges this was more efficient than the built in method. I no longer remember why or who credit for this hack originally belongs to.