Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Upcoming SlideShare
×

# Str8ts Weekly Extreme #59 - Solution

1,355 views

Published on

Solution to the weekly extreme Str8ts puzzle #59 from www.str8ts.com

• Full Name
Comment goes here.

Are you sure you want to Yes No
Your message goes here
• Be the first to comment

• Be the first to like this

### Str8ts Weekly Extreme #59 - Solution

1. 1. Weekly Extreme Str8ts Puzzle #59 August 7 – August 13, 2011www.str8ts.com<br />Solution & puzzle bySlowThinker<br />
2. 2. Start position<br />Extreme Str8ts #59 was designed by me, and it has a peculiar feature that is the central focus of this puzzle.<br />
3. 3. Solving…<br />Removing stranded digits eliminates many candidates at this point…<br />A5=4d<br />C5=3c <br />A4=5<br />C4=2<br />
4. 4. Solving…<br />C7=1s<br />A2=89, because of C..G2, therefore C..G2 cannot contain a 9 as it would leave A2 without candidates.<br />Also, 1 is a stranded digit in D3.<br />
5. 5. Solving…<br />G3=1s<br />G6=2s<br />F7=2s<br />A2=9p<br />… and because of the pair 78 in CF2, we can remove 3 as candidate from DE2.<br />
6. 6. Solving…<br />Because of E2=46 we can remove 2 from E3 (stranded) and 9 from E13 (range check.)<br />D3=2s<br />D2=4c<br />D4=3<br />D5=5<br />
7. 7. Solving…<br />E2=6<br />B4=4<br />B3=3p<br />G1=6s<br />D9=6s<br />
8. 8. Setti’s rule on 6<br />There are 8 rows that have a 6, so 8 columns must contain a 6 too  GHJ5 contains a 6.<br />Note that E5 cannot be 5 or 8 due to E123 and E789.<br />
9. 9. Unique solution constraint<br />This is the key point of this puzzle: looking at E5 we find that of all fields that influence E5, only E789 affects E5. Thus if E789 would notcontain a 9, E5 could be either 1 or 9 which would violate the unique solution constraint <br />E789=789u<br />E5=1u<br />
10. 10. Solving…<br />E2=4h<br />E3=5h<br />F8=5s<br />B6=6h<br />B7=5<br />
11. 11. Solving…<br />Due to H1, H3..7 cannot end at 9, as this would leave H1 without candidates <br />H4=7h<br />G4=9<br />C1=9p<br />C9=5p<br />
12. 12. Solving…<br />H1=8<br />F1=7<br />F2=8<br />F3=9<br />C2=7<br />C6=8<br />
13. 13. Solving…<br />A6=7<br />H3=6<br />H7=4<br />H5=5<br />H6=3<br />F6=4<br />
14. 14. Solving…<br />A3=8<br />A7=6<br />J3=7<br />J5=6<br />J6=5<br />J7=9<br />
15. 15. Solving…<br />J8=4c<br />G5=7c<br />G8=8<br />D8=7<br />D7=8<br />F9=3<br />
16. 16. Solving…<br />E7=7<br />E8=9<br />E9=8<br />G9=4<br />B9=7c<br />
17. 17. Solution<br />This puzzle showed that the unique solution constraint not only comes in form of a unique rectangle, but also in terms of compartments influencing each other.<br />For more information see my strategy slides.<br />
18. 18. Glossary<br />Letters appended to steps indicate the last strategy used, just before filling in a field:<br />No letter … number was last candidate in field<br />s … single (last) candidate for that number in compartment<br />c … compartment range check<br />d … stranded (unreachable/impossible) digits removed<br />h … high/low range check across compartments<br />p/t/q … naked pair / naked triple / naked quadruple<br />ph/th/qh … hidden pair / hidden triple / hidden quadruple<br />x … X-wing (2 rows / 2 columns)<br />w … Swordfish (3 rows / 3 columns)<br />j … Jellyfish (4 rows / 4 columns)<br />L … large gap field<br />Sx … Setti’s rule (count the numbers rule) – ‘x’ is the analysed number<br />u … unique rectangle<br />y … Y-Wing or XY-chains<br />
19. 19. Weekly Extreme Str8ts Puzzle #59www.str8ts.com<br />Solution by SlowThinker<br />Note: there are other (maybe easier) ways to solve this puzzle.<br />View & download my strategy slides from:<br />http://slideshare.net/SlowThinker/str8ts-basic-and-advanced-strategies<br />or from Google Docs:<br />http://is.gd/slowthinker_str8ts_strategy<br />