Codeforces Round 508 (Div. 2) D. Slime
Codeforces Round 510 (Div. 2) D. Petya and Array
Codeforces Round 520 (Div. 2) D. Fun with Integers
Codeforces Round 516 (Div. 1, by Moscow Team Olympiad) B. Labyrinth
Codeforces Round 515 (Div. 3) D. Boxes Packing
Poisoned Food
Plants
Prefix Free Subset
Point in Kgon
Clown Fiesta