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: Jota (jota) on Jun 13, 2019
Any memories Tom?#2: BlackCat (BlackCat) on Jul 21, 2020
No idea#3: Vaggelis Kamaris (evag7651) on Dec 27, 2021
solved. one revert at the end.#4: Bill Eisenmann (Bullet) on Sep 19, 2022
Ollie doin' a little dance!#5: Jill Tallmer (Yidl) on Oct 2, 2022
Is Ollie an owl?#6: Web Paint-By-Number Robot (webpbn) on Apr 1, 2023
Found to have a unique solution by wombatilim.#7: Web Paint-By-Number Robot (webpbn) on Apr 1, 2023
Found to be solvable with moderate lookahead by wombatilim.#8: Wombat (wombatilim) on Apr 1, 2023 [HINT]
Initial LL completes 16%.
R1: EL places blacks in C18-20. LL.
R2: Deep EL (v.R5) marks C2-3 and C16-17 white. LL.
R3: EL v.R5 places blacks in C10-12. LL.
C4: EL marks C16-17 white. LL.
R5: There are blacks in C8 and C11. One of these must be the 1. This means at least one of C9-10 goes into R2, so R2C15 can be marked white.
C23: If the 2 is placed in R5-6, it makes C24 invalid, so these squares are white.
R24: EL marks C1-2 white. LL.
R5: If the black in C8 is the 1, it put blacks in R2 C7-9 and then R5C12, which makes R5 invalid. Therefore R5C8 must be part of the first 2. R5 C1-6, C10, and C12 are white. LL.
C7: Whether the 3 goes into R3 or R6, R7-8 C9 are black. LL.
C15: Whether the 2 goes into R22 or R24, it starts the 2 in C16. R17-20 C16 are white. Minimal LL.
C15: If the 2 goes into R22, the 2 in C17 is placed in R20-21 in 2 moves. If the 2 goes into R24, the 2 in C17 is in R24-25. Either way, R16-19 and R22-23 in C17 are white.
C17: If the 2 is in R20-21, R20C18 is black. If the 2 is in R24-25, R25C18 is black. Either of these completes C18, so R15-19 and R21-24 in C18 are white. LL.
C15: If the 2 goes into R24, the black in R22C22 is determined to be the 1 in C22 in 2 moves, and R21 is made invalid. R22C15 is black instead. LL.
C25: If the 2 is placed in R24-25, R23 is made invalid, so it must go into R21-22 instead.
LL to finish.
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