Div.1:
- https://qoj.ac/problem/1515
- https://qoj.ac/problem/1516
- https://official.contest.yandex.ru/opencupXVII/contest/3176/problems/3/
- https://open.kattis.com/problems/ascendingphoto
- https://community.topcoder.com/stat?c=problem_statement&pm=17082&rd=18756
Div.1 + Div.2:
- https://open.kattis.com/problems/glyphrecognition
- https://community.topcoder.com/stat?c=problem_statement&pm=17083&rd=18756
Div.2: