Codeforces Round #500 (Div. 1) [based on EJOI] A. Photo of The Sky
Technocup 2019 - Elimination Round 2 B. Curiosity Has No Limits
Codeforces Round #519 by Botan Investments C. Smallest Word
Distinct Subsequences
Unique Paths in a Grid
Max Product Subarray
Ways to Decode
Max Sum Path in Binary Tree
C - Row Column Sums
B - Dividing Subsequence