April 9, 2016
Problem statement
Category: Difficult problem
Spend 25 minutes to think about problem, and then will get into other people's submission, and see what should be learned.
10:30 am - 10:55 am
Spent 25 minutes to think about the problem.
Try to express the expression using binary tree, like 1 + 2 * 3 problem using a tree.
So, ab can be express as a tree:
operator .
/ \
a b
a|b
operator |
/ \
a b
a*
put * as parent node, and a is left child of operator node *
(a*)5
put 5 as the parent node of operator *
Structure the input as tree structure, and then, define different class - concatOp, orOp, starOp
Read the expression from left to right, and then, put it into data structure like a stack, and then, parse it, store it in the binary tree.
April 10, 2016 2:32 pm
This is a graph problem, and also, the NFA, DFA problem. Julia, you are lucky to review the problem. Spend some time in the short future to go over code, give yourself a graph coding experience.
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