1936 All in All (1)
Hint: It's like a 2D DP problem, but there is a lot faster way.
2408 Anagram Groups (2)
2359 Questions (3)
1750 Dictionary (3)
2752 Seek the Name, Seek the Fame (4)
1961 Period (5)
1147 Binary codes (6)
3261 Milk Patterns (6)
2185 Milking Grid (7)
3349 Snowflake Snow Snowflakes (7)
3167 Cow Patterns (8, challenge problem)
2774 Long Long Message (9, challenge problem)