Topics Covered

(* Indicates a problem I struggled to implement correctly and need to review later)

Cracking the Coding Interview

1.1 - Is Unique
1.2 - Check Permutation
1.3 - URLify
1.4 - Palindrome Permutation
1.5 - One Away -> See generatePermutations and printNumbersWithBase under Helpful_Problems for examples of the naive case.
1.6 - String Compression
1.7* - Rotate Matrix
1.8* - Zero Matrix
1.9 - String Rotation -> Had difficulty visualizing what a rotation was, becomes easier once able to visualize. Also see isSubstring under Helpful_Problems.

2.1 - Remove Dups
2.2 - Return Kth to Last
2.3 - Delete Middle Node -> I overcomplicated this one on my first attempt. This is as simple as finding the node before the one to remove, and changing its pointer to the one after it.
2.4 - Partition
2.5 - Sum Lists
2.6 - Palindrome
2.7* - Intersection -> The O(n) time and O(1) space solution to this problem was a little tricky, worth looking at again.
2.8* - Loop Detection -> This one requires you to know the "Tortoise and the Hare" algorithm for its best solution. I would recommend reviewing this algorithm in detail, especially how to return the index of the start of the cycle.

3.1* - Three in One -> This one is simple in theory, but difficult to fully implement, because there are alot of areas where you can get out of bounds exceptions.
3.2* - Stack Min -> Tricky at first, but simple when you realize that additional space complexity is required.
3.3 - Stack of Plates
3.4 - Queue via Stacks
3.5* - Sort Stack
3.6 - Animal Shelter