I hope you guys enjoyed the contest — I hope to host another one soon :D
With that said, here are the tutorials:
Tutorial is loading...
Author's Code: 42591712
Tutorial is loading...
Author's Code: 42591830
Tutorial is loading...
Author's Code: 42591846
Tutorial is loading...
Author's Code: 42591882
Tutorial is loading...
Author's Code: 42592019
Tutorial is loading...
Author's Code: 42592026
Tester(cdkrot)'s Code: 42593206
For O(n3) solution, refer to this comment by pranjal.ssh