Michelle Tyler @seekingshell

@LBCityLibrary Thanks for responding quickly!

@LBCityLibrary do you take children's book donations? I have a small box of them for an elementary school level reading ability. Most of them are from the babysitters series.

@LBCityLibrary Understandable. Is there a date set when this will be available again or is it indefinite at this time?

@ARasheedPhoto Thank you 😊

Leetcode 30 Day Challenge, Day 30. Given a binary tree and a sequence of nums, find if sequence is valid where start node must be root and end is a leaf. Similar to the last problem, I used a HashMap to track visited nodes. I then used a stack to track the sequence. I'm done! 😍

Leetcode 30 Day Challenge, Day 29. Given a non-empty binary tree, find the max path sum. I navigated the tree via postorder traversal using one stack. I had to cache the max at each node for reference, so I used a HashMap. I am getting better at recognizing traversal strategy! 😍

Leetcode 30 Day Challenge, Day 28. Given a queue of nums, find the first unique num. Since the problem requires add but not remove, I used similar data structure strategy to the LRU cache problem: doubly linked list and hashmap. A node in list is removed when num isn't unique.

Leetcode 30 Day Challenge, Day 27. Given a binary matrix, find the area of the largest square of 1s. I need to review DP strategy! Start with top-down, see the pattern, and apply with bottom-up. Remember, squares are made of other squares! Optimize memory based on lookup pattern.

Leetcode 30 Day Challenge, Day 26. Given two strings, find the longest common subsequence where you can delete elements not found. Very similar method to finding shortest path, except we're tracking count of common chars in our DP matrix and we want to propagate the max, not min.

Currently watching the HellaConf 2020 Twitch stream to learn more about Application Security 😍. Check out the schedule and link to the stream below! hella-secure.com/hellaconf-2020/ #HellaConf2020 #appsec #learnsomethingnew

Leetcode 30 Day Challenge, Day 25. Given an array of nums that hold max jump length to another position in the array, determine if you can reach the last index from the first. Using DP, start from the right to see if your jump value can at least make it to the last good position.

@g0nvds Absolutely! Good luck 😊

Leetcode 30 Day Challenge, Day 24. Implement a LRU cache. I found out there's an existing data structure in Java that does this called LinkedHashMap. I wanted to implement my own hashmap index and doubly linked list cache. I remember now how painful doubly linked lists can be! 😂

Leetcode 30 Day Challenge, Day 23. Given two numbers that represent a range, find the bitwise AND of all nums in this range inclusively. Comparing each bit, the idea is to find the bit location where the values diverge. This is the point of fluctuation with each num in the range.

Leetcode 30 Day Challenge, Day 22. Given an array of nums, find the total number of contiguous arrays whose sum equals given k. Sound familiar? While saving previous sums, if you can subtract k from current sum and get a sum you've seen before, then you have a sum equal to k!

Leetcode 30 Day Challenge, Day 21. Given a binary matrix, find the first column with a 1. Every row is sorted increasing order. The catch? You are limited to 1000 matrix value lookups. Brute Force won't scale, so I use binary search and one conditional to drastically cut lookups.

Leetcode 30 Day Challenge, Day 20. Given an preorder traversal array, construct a binary search tree. Funny enough, my first idea ended up being the solution I went with, but I kept doubting myself and would switch. Lesson learned, go with your gut! 😍