two problems with low AC rate, but not too hard.
a diao bao le one!
passed OJ, the corner case about the leading 0's is fixed
Hard One! definitely need to do it more times
another example of sliding window
fixed a compile warning
easy one, but need to pay attention how to implement it concisely and correctly
Not the best solution, but ACed by OJ
easy one, not sure whether there are better solution
ACed, bottom up one
Bad bad one
easy DFS
adjust packages
Two math problems, no sense, remember them