FINALLY all coding bat problems solved!

OK, i did not solve all of the last section (Recursion-2) problems, backtracking was new to me. I looked up ONLY SOME SOLUTIONS. but I feel proud!
in short, i solved about 90% of all  problems MYSELF.

coding bat is certainly not a match to real competitions, but it is a good result for a newbie like me, now i have some confidence to raise the limit!
i spent about 5 months doing it : 1 june 2013 - october 22 2013