A. BowWow and the Timetable

题意可以简化为求

$$\frac{\lceil log_{2}s \rceil}{\lceil log_{2}4 \rceil}$$

即$\frac{\lceil log_{2}s\rceil}{2}$

B. Mislove Has Lost an Array

C. Anna, Svyatoslav and Maps

D1. Kirk and a Binary String (easy version)

D2. Kirk and a Binary String (hard version)

E. Natasha, Sasha and the Prefix Sums