Day 3:
Linked list is done. One solution would be added for problem 6, recursive solution.
New technique: racer iterator, let the condition check for both the current node and the next node. If the fast iterator endup with a existed address(tail), it means the linkedlist has an odd length. Very useful technique when doing linkedlist problems.
Today's feeling: need to be more patient about coding,could avoid lots of useless error when being patiance and coding carefully.
Tomorrow would focus on stack & queue.Gonna finish them all.