• Dec 21, 2019

  • Walked 4 miles around Atherton.
  • Chan Sung Jung knocked out Frankie Edgar (38), and now there isn’t an event for the next 4 weeks until McGregor Cerrone.
  • All presents wrapped and ready. Dec 21st. World record.
  • SCORE_DAYS was the nominal th/sun/mon. I had to add saturday for these week 16 games. Deployed the supercontest change. Recompiled reqs.
  • Did a few hackerrank problems:
  • https://www.hackerrank.com/challenges/tree-height-of-a-binary-tree.
  • https://www.hackerrank.com/challenges/tree-level-order-traversal.
  • https://www.hackerrank.com/challenges/balanced-brackets.
  • https://www.hackerrank.com/challenges/contacts.
  • https://www.hackerrank.com/challenges/find-the-running-median.
  • Side note: hackerrank has a terrible problemsolving interface. The inputs are given via stdin with line separations lol, and the outputs are compared to stdout. This is probably laziness to accommodate multiple languages, but it’s shrouded and detracting.
  • The difficulty is also widely variant. I finished some “medium” level questions in (literally) 60 seconds, and some “easy” questions took my 20 minutes to read the problem statement and 40m to answer.
  • Some complexity notes.
  • Recursion with 2 recursive calls is exponential in time complexity.
  • Binary trees require 2 recursive calls to traverse, one to walk the left edge and one for the right.
  • Fibonacci sequences require two recursive calls as well, but you can memoize each one to reduce it from exponential to linear.
  • For iteration problems, usually just run a while loop and add items to array, or do something else to keep track as you traverse.