【APIO2020】有趣的旅途
【Codeforces 1120E】The very same Munchhausen
【Codeforces 1019C】Sergey's problem
【Codeforces 1168E】Xor Permutations
【Codeforces 1292E】Rin and The Unknown Flower
【AtCoder Regular Contest 084 E】Finite Encyclopedia of Integer Sequences
【AtCoder Regular Contest 083 E】Bichrome Tree
【AtCoder Regular Contest 079 F】Namori Grundy
【AtCoder Regular Contest 070 F】HonestOrUnkind
【AtCoder Regular Contest 063 E】Integers on a Tree
