Simple explanation here I think, unless I misunderstood the question. Two posts were pending approval as they were first time posts from people, and some of us were away for the weekend and slow to approve it.

Preliminary+results+have+been+published%2E+%0D%0AI+ask+Christian+to+check+his+Hitori%2E+%0D%0ANikola+and+Du%D1%81%2C+please+check+your+answers+to+puzzle+12%2E+The+lines+should+not+overlap%2E+

Oh+wow%2C+thank+you+for+a+great+contest+Riad%21+The+puzzles+were+hard%2C+but+they+are+always+hard%2E+And+thank+you+to+all+the+contestants+with+short+names%2E+%F0%9F%98%8E%0D%0AI+don%27t+think+anybody+has+got+100+points+before%2E+If+it+is+useful+for+others%2C+I+will+share+some+thoughts+on+how+I+approached+them%2E%0D%0A%0D%0AOpti%2DSumdoku%3A+%0D%0AThe+first+step+was+to+find+a+grid+with+a+high+Samedoku+score%2E+I+looked+at+patterns+for+each+digit+separately%2E+It+is+not+possible+to+place+a+digit+in+9+cells+so+that+it+counts+18+times+to+the+sum+%28when+every+digit+can+see+another+digit+in+both+diagonal+directions%29%2E+The+best+possible+is+16+times+%28see+the+9s+in+my+solution%29%2E+But+not+all+digits+can+be+16+%2D+the+best+grid+overall+has+%7B16%2C+15%2C+15%2C+14%2C+14%2C+14%2C+14%2C+14%2C+14%7D+for+the+Samedoku%2E+I+think+Carlos+has+the+same+grid+as+me%2E%0D%0AThe+second+step+is+to+take+away+as+many+digits+as+possible%2E+Check+for+uniqueness%2C+try+another+digit%2E+Eventually+you+will+get+down+to+%7E22+clues%2E%0D%0AThe+last+step+is+to+choose+which+digit+goes+in+each+part+of+the+grid+pattern%2E+Calculate+16%2F15%2F14+minus+the+number+of+hints+remaining+%28e%2Eg%2E+9+gets+the+best+place+%3D+16%2D1%2C+8+gets+the+14%2D0%2C+7+gets+15%2D2%29%2E+%0D%0APlease+don%27t+try+to+solve+my+classic+sudoku%21+It+is+unique%2C+but+it+needs+a+lot+of+Xwings%2C+Ywings%2C+chains%2E%2E%2E+%F0%9F%98%AD%0D%0A%0D%0AName+Hitori%3A%0D%0AI+decided+to+use+all+the+2%2Dletter+and+3+words%2C+and+many+4s%2C+and+I+ignored+all+5%5FPLUS%5F+words%2E%0D%0AIt+is+easy+to+have+too+many+blacks%2C+or+not+enough+blacks%2C+so+I+started+by+trying+to+intersect+many+4%2Dwords+together%2E%0D%0AI+found+a+4x4+with+6+4%2Dwords+inside%2C+I+put+that+in+the+bottom%2Dleft+corner%2E+I+found+another+4x4+with+6+words+inside%2E+When+I+put+that+in+the+bottom%2Dright%2C+the+common+letters+%28e%2Eg%2E+ADEM%2DENDO%29+helped+fill+90%25+of+those+cells+with+black+or+white%2E+I+filled+the+top%2Dright+with+4%2Dwords+too%2C+sometimes+choosing+letters+for+Hitori%2C+sometimes+choosing+for+intersection%2E+At+the+end+I+put+the+final+2%2D+and+3%2Dwords+in+the+gaps%2E+I+had+two+empty+cells%2E+One+I+used+to+finish+the+Hitori%2C+and+one+was+a+bonus+point%2E%0D%0A%0D%0AThreads+With+Knots%3A%0D%0AI+wanted+to+start+with+long+diagonal+lines+for+the+1st%2C+3rd%2C+5th%2C+7th+sections+to+get+a+high+length%2E+I+put+small+numbers+near+the+corners%2E+The+8%2C5%2C3%2C7+clues+define+knots+1+to+7%2E+The+2+clue+is+not+needed%2C+but+it+did+give+lots+of+empty+squares+on+the+long+diagonal%2E+%0D%0AThen+I+switched+to+finding+a+unique+solution+with+small+clues%2E+Thread+length+was+less+important+now%2E+Putting+clues+on+the+same+parity%2Fcolour+diagonals+helped+too%2E+I+found+two+medium+numbers+%289%2C+13%29+to+finish%2E%0D%0ASP1+and+EKBM+both+had+much+better+clues+than+me%2C+but+my+long+thread+was+important%2E+It+is+possible+to+have+length+%3E+100%2C+but+then+you+need+too+many+big+clues+to+make+it+unique%2E

Riad, thanks for organizing a great contest!
And congratulations to kiwijam for a perfect win!!!
Thanks also to the LMI team for running the event.
I had not participated in this contest for a few years, but I really enjoyed it.

I especially like prob. 7 and 12.
I didn't have time to fix my solution for 12 because it was the last day of the contest when I realized that the length of lines was important.I regret that.
Anyway, I think prob.12 is a really good optimization setup!

I like optimization puzzles very much, and I am very happy to see the April Contest where I can enjoy them.
I'm planning to hold an optimization contest at a local site in Japan.
I hope that the fun of optimization will spread more and more.

Edited by SP1 2025-04-29 10:13 PM

Thanks a lot to everyone!
Congratulations to James, Takuma and Paul!
Success in optimization problems in 2025 earned more points than ever. James had a very impressive victory. Only two participants managed to score points in all optimizations. Takuma, great result! Interestingly written in the two posts above. I wish Takuma success in organizing the optimization contest in Japan.
There were questions like: Why ban word overlapping in Hitori? I think through the answer format so that it is convenient for the organizers. A lot of parentheses can prevent Deb from forming grids with solutions. For clarity, it is better to place the parentheses sequentially. Thanks to the LMI team, Deb and Prasanna, and a special thanks to Kota for the long-term support!

Thanks Riad and well done James! Are there solutions available to the puzzles? I had a tough time with some of them and was hoping to work through them with the solutions.