If you are using an IDE like Eclipse or anything with auto code completion, syntax color-highlighting, and syntax error highlighting, get rid of that while coding up the exercises in the PDF.

Use Notepad++ or kwrite and disable those features, if your coding speed grinds to a halt under these conditions, good!

That's the point of the exercise, like trying to jog at 30 thousand feet, as you overcome the hindrance up there, and you come back down to normal level, you feel like you can leap over a car. Same with coding, you feel like you can code blindfolded. And your ability/productivity increases by an order of magnitude.