- Amazon is making a palm reader payment service.
- Placed some tsla calls, but in bigger news, the $1000 1yr is over $45. Ridiculous.
- Added KTN and FFN to the chicago flight.
- Popular hash functions: MD5, SHA, NTLM, LANMAN.
- FB coding interview. This guy was awesome. Did well, good convo.
- Great answer to my question, Future success in data or product? It’s neither. It’s having the best tech stack, the best engineering talent. This will make you more agile in bringing NEW products to market in the future, whatever that landscape may look like.
- Practice problems.
- https://leetcode.com/problems/word-break/. Did it very fast with my recursive solution, but need a way to memoize. DP is crucial for this one. Think about it logically. Try every word at every starting position, and mark the index of the end of the word as findable if there are any matches. I still like my solution better.
- https://leetcode.com/problems/min-stack/. Build your own stack.
- Max path length in tree. This is the same as max path sum (https://leetcode.com/problems/binary-tree-maximum-path-sum/), but treat each val as 1 (unweighted, basically). It’s a recursion problem. Look to the left, recurse to the max depth there. Look to the right, recurse to the max depth there. Add the two together. That’s the max path for this root. Keep a global variable for the max found so far, and then on each recursion just check against it.
- https://leetcode.com/problems/gas-station/. This one was weirdly hard. There’s such a wide variety in problems. I crush some “hard” ones, some “medium” ones are impossible. There’s definitely a bit of luck in the selection of the questions interviewers ask you.
- https://leetcode.com/problems/longest-consecutive-sequence. Smartly keep track of visited nodes in sets. Little harder than it appears, but approach logically. The hard part of this one is the recognizing the complicated for/while solution is actually only n, not nested n^2, because you’re checking existence in set.
- https://leetcode.com/problems/copy-list-with-random-pointer/. Deep copy a linked list, iterate through and keep track of a few things. A different type of problem. Can recurse like usual, and assign both pointers, with one tricky part: keep a memoization dict of the visited nodes. This is just a mapping of original node -> copied node.
- https://leetcode.com/problems/palindrome-partitioning/. This one is tough too. I’ll have to do some easy/medium to get up for tomorrow. Remember that recursion is almost always a good answer, even for string/list problems. Iterate through the beginning till you hit some criteria, then recurse on the remainder. Keep track of all valid answers in a global variable, rather that directly in the recursive call scope.
- Flew to chicago for citadel.
- FB uses mercurial, not git.
- Scheduled the amazon sr followup for friday, 1-3.
- Citadel research.
- 10s of billions of assets under management.
- Ken Griffin founder, Peng Zhao current CEO.
- Reviewed my tradebot.
- Nasdaq for all tickers on the nyse.
- Yahoo-fin and robin-stocks for history/data.
- Backtrader for backtesting.
- Simple moving average (and a few other basic one) for strategies.
- Robin-stocks to wrap the rh api.
- Scikit-learn/numpy/pandas/matplotlib for analysis.