OP has posted this link before, both here https://news.ycombinator.com/item?id=10990206 (with the title "Get an interview at LinkedIn by solving this puzzle") and on the Who's Hiring threads https://news.ycombinator.com/item?id=11014173 As an exercise, I wrote a quick and dirty python script to solve this back in February (albeit it's not the most elegant solution but far better than brute force) and submitted my ans…
> not the most elegant solution but far better than brute force
Actually, brute force works just fine for such a small matrix: