Solution to Tarek's Fluid Drive #8 (SE 10.5)

Advanced methods and approaches for solving Sudoku puzzles

Solution to Tarek's Fluid Drive #8 (SE 10.5)

.
Solution to Tarek's Fluid Drive #8
Code: Select all
` *-----------* |9..|..1|8..| |.6.|.3.|...| |..2|5..|..7| |---+---+---| |..9|...|..6| |.5.|...|.2.| |4..|...|3..| |---+---+---| |3..|..8|1..| |...|.4.|.8.| |..7|9..|..5|   SE=10.5, gsfr=99789, Suexr=930 *-----------*`

NOTE: "..." denotes steps using Simple Sudoku program.
Sub-nets are enclosed thus: (?xay...??) and sub-sub-nets thus: ((?xay...??)).

SOLUTION:

(1) -3e5(MC)

(2) ?5g3..., -3d4(Swordfish 3aeh349)... (?3a9..., -8e5(MC)... ((?1b3...??))-1b3, 8b3...??) -3a9...?? -5g3, 5g5.

(3) ?5b3..., -7e4(colours)... (?3d6...??)-3d6... (?3a9...??)-3a9..., -6h3(MC)... (?3a2...??)-3a2..., -7e5(colours)..., -7d6(X-Wing 7be16)...?? -5b3.

(4) ?5b8..., -7e4(colours)..., -8f6(MC)... (?3d6..., -4b7(MC)... ((?6g3...??))-6g3, 4g3...??) -3d6..., -8b1e15f2(Swordfish 8cdk125), (?3a9..., -2d25k257(X-Wing 2dk16), -4b7(MC), ((?1c1...??))-1c1, 8c1...??) -3a9... (?1c1..., -7e5(MC)... ((?8f3...??))-8f3, 1f3...??) -1c1, 8c1...?? -5b8.

(5) ?5f8..., -8b1e15f25(Swordfish 8cdk125), (?3a2..., -7e4(colours), -1f5(MC), -6e4(MC), -7e5(MC), -9c7(XY-Wing 179bd8e7)...??) -3a2... (?3a9...??)-3a9... (?1c1...??)-1c1, 8c1...?? -5f8, 5f6.

(6) ?5b7..., -2d4(MC), -8f5(MC)... (?3a8..., -8b1e15f2(Swordfish 8cdk125), -6h3(MC)...??) -3a8, (?3c8..., -1e15f25h2(Swordfish 1cdk125), -8e15f2(Swordfish 8cdk125)...??) -3c8...?? -5b7...

(7) ?3d6...?? -3d6...

(8) ?3a9...?? -3a9..., -4g9(MC).

(9) ?8c1...?? -8c1, 1c1.

(10) ?9c5...?? -9c5...

(11) ?1f3...?? -1f3...

(12) ?2f2...?? -2f2...End.

Tarek, a very fine and tough puzzle, it need stand back for no other in my opinion. My solution is longer than usual, with 3 sub-sub-nets.

My strategy here was what is becoming standard for me: attack the weak candidates ( those with sparse distribution, as opposed to compact distribution) in tandem (here the 5s first, with subnets on the 3s). Then, whenever no candidates appear attractive, attack the bivalue cells. (By this time, there will BE more of those.)
___________________________
gurth

Posts: 358
Joined: 11 February 2006
Location: Cape Town, South Africa

To compare:
This is my program's solution (no subnets, coloring, xy-wing, swordfish):
r6c5<>1, r4c5<>5, r5c5<>8, r6c5<>8, r8c1<>1, r5c6<>3, r4c1<>1, r2c1<>1, r2c3<>1, r9c6<>6, r2c1<>8, r2c3<>5, r3c2<>1, r7c8<>4, r8c9<>9, r4c6<>3, r7c3<>5, r8c3<>1, r7c3<>6, r7c2<>9, r4c8<>1, r1c2<>3
ravel

Posts: 998
Joined: 21 February 2006

Thanx gurth & ravel for your efforts & kind comments.......... This puzle as far as I know is the hardest which Explainer can tackle........ ...

I have no Jade to present though

tarek

tarek

Posts: 2755
Joined: 05 January 2006