Round 77: Two Rows

DP state = cost(col, isFirstRow, isFirstRowFilled, isSecondRowFilled, isFirstPlayer)

Round 77: Expected Lcp

Uses trie

Round 78: Banned Digits

Starndard DP - With the same prefix, how many #s we can assemble given the constraint

  1. go for possible #s < next digit, and then pow of remaninings

  2. go for the same digit, keep going

Round 78: Strange Matrix

Uses segment tree