Right view of Binary tree
Pairwise Xors
Penalty Shoot-out
Magical Girl and Colored Liquid Potions
Count Relations
Counting Inversions Revisited
Codeforces Round #796 (Div. 1) A. The Enchanted Forest
Codeforces Round #798 (Div. 2) C. Infected Tree
Codeforces Round #803 (Div. 2) D. Fixed Point Guessing
Codeforces Round #805 (Div. 3) E. Split Into Two Sets