Binary Shuffle
Chef got Recipes
Same Parity Swaps in Binary Strings
Palindromic Game
Eugene and function
Codeforces Round #635 (Div. 1) A. Linova and Kingdom
Educational Codeforces Round 86 (Rated for Div. 2) C. Yet Another Counting Problem
Codeforces Round #639 (Div. 1) A. Hilbert’s Hotel
Codeforces Round #638 (Div. 2) C. Phoenix and Distribution
Codeforces Round #641 (Div. 1) A. Orac and LCM