Leetcode: ~350 total (80 easy, 220 medium, 50 hard)

Facebook, L5, Offer

• phone screen
  https://leetcode.com/problems/read-n-characters-given-read4-ii-call-multiple-times/
  https://leetcode.com/problems/remove-linked-list-elements/

• onsite coding 1
  https://leetcode.com/problems/insert-into-a-sorted-circular-linked-list/
  https://leetcode.com/problems/decode-string/

• onsite coding 2
  https://leetcode.com/problems/valid-palindrome-ii/
  https://leetcode.com/problems/verifying-an-alien-dictionary/

• system design
  design Android app that updates wallpaper each time when you lock your phone, images for the wallpapers are downloaded from your facebook account

Google, L4, Offer

• phone screen
  https://leetcode.com/discuss/interview-question/423264/Google-or-Phone-Screen-or-Second-Max-or-Reject/383427

• onsite coding 1
  https://leetcode.com/discuss/interview-question/884712/google-phone-data-structure-for-storing-ranges

• onsite coding 2
  check if there is a square of 1s in a 2d matrix (that contains 0s and 1s). the square has the size of at least sqrt(min(N,M)). the input either has one valid square or not (all 0s).

bool hasSquare(int[][] matrix)

• onsite android-specific
  general android questions (how to optimize scrolling performance, how to implement background operations, testing)

• system design
  design multiplayer battleship game