「AtCoder Beginner Contest」#263

「Edu Codeforces Round」#133 (Div 2)

「杂题选讲」#2

NowCoderL101E 水没都市 题解

「Codeforces Round」#811 (Div 3)

NowCoderT62B 置换 题解

CF1493D GCD of an Array 题解

CF1389E Calendar Ambiguity 题解

CF893E Counting Arrays 题解

CF615D Multipliers 题解