Comments on Puzzle #27301: Diving
By Hanhong Xue (macroxue)
peek at solution solve puzzle
quality: 
difficulty: 
solvability: moderate lookahead
peek at solution solve puzzle
quality: difficulty: solvability: moderate lookahead
Puzzle Description:
(This puzzle was recovered from the 2016 database crash. Puzzle creators, please edit this puzzle and put the real description here!)
#1: Web Paint-By-Number Robot (webpbn) on Apr 17, 2023
Found to have a unique solution by wombatilim.#2: Web Paint-By-Number Robot (webpbn) on Apr 17, 2023
Found to be solvable with moderate lookahead by wombatilim.#3: Wombat (wombatilim) on Apr 17, 2023 [HINT]
Initial LL completes 47%.
C29: EL marks R1-7 and R32 white. LL.
R1: EL marks C1-6 white.
R2: EL marks C1-4 white.
R3: EL marks C1-4 white.
R2: EL marks C5-6 white.
C22: If R12-14 are part of the 7, R7-8 C19 are black. R1-6 are white in C19 and C22, which also marks those rows white in C20-21. This makes C20 invalid. Therefore R12-14 C22 must be the 3. LL.
C21: If either R20 or R21 is black, regardless of whether it is the 1 or the 2, C18 is invalid. These squares must be white. LL.
R15: EL marks C1-4 white.
R16: EL marks C1 white. Minimal LL.
R16: If the 4 is in C2-5, either R15 or R17 will be invalid. R16 C2-3 are white. LL.
R15: EL now marks C5-6 white.
R28: EL marks C1-3 white. If C4 is black, the 1 in C4 will have nowhere to go, so C4 is white as well.
R17: EL marks C30 white.
R28: EL marks C30 white.
R35: EL marks C30 white.
C2: If R29-30 are black, there is nowhere to place the other 2 that doesn’t make something invalid. Therefore R29C2 is white. LL.
R35: EL marks C4-6 and C16-17 white. LL.
R35: If the 9 is in C7-15, R33 will be invalid, so these squares are white. LL.
R15: Whether the 4 goes to C11 or C15, R16C11 is black. Minimal LL.
R35: If the 9 goes to C18, R33 will be invalid. R35C27 is black instead. LL.
C6: Whether the bottom 2 goes to R32 or R34, R33 C8-10 are white.
R33: EL marks C19-20 and C30 white. LL.
C21: If R18 or R19 is black, C18 is invalid, so these are both white. LL.
R31: EL marks C30 white.
C20: If the 2 is placed in R31-32, R31 would need to place black in C20-29 and R32 would need to place black in C11-20. C18 would be invalid. Therefore R30C20 must be black.
LL to finish.
You must register and log in to be able to participate in this discussion.