Analysis of xx-top95-075-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .52..68.......7.2.......6....48..9..2..41......1.....8..61..38.....9...63..6..1.9 initial

Autosolve

position: .52..68.......7.2......16....48..9..2..41......1.....8..61..38.....9...63..6..1.9 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # D3: 3,9 => CTR => D3: 2,5
* PRF # E3: 3,4 => SOL
* DIS # H3: 4,5 => CTR => H3: 3,7,9
* DIS # E2: 4,5 => CTR => E2: 3,8
* DIS # G8: 4,5 => CTR => G8: 2,7
* DIS # H4: 5,7 => CTR => H4: 1,3,6
* DIS # I4: 5,7 => CTR => I4: 1,2,3
* DIS # H5: 5,7 => CTR => H5: 3,6
* DIS # H6: 5,7 => CTR => H6: 3,4,6
* DIS # G8: 5,7 => CTR => G8: 2,4
* CNT  10 HDP CHAINS /  33 HYP OPENED

See Appendix: Full HDP Chains for full list of HDP chains.

Pair Reduction

Pair Reduction

The following important HDP chains were detected:

* DIS # D3: 3,9 => CTR => D3: 2,5
* PRF D3: 2,5 # E3: 3,4 => SOL
* STA D3: 2,5 + E3: 3,4
* CNT   2 HDP CHAINS /   8 HYP OPENED

See Appendix: Full HDP Chains for full list of HDP chains.

Details

Positions

.52..68.......7.2.......6....48..9..2..41......1.....8..61..38.....9...63..6..1.9 initial
.52..68.......7.2......16....48..9..2..41......1.....8..61..38.....9...63..6..1.9 autosolve
152946837963587421847231695574863912289415763631729548796152384415398276328674159 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (4)
D1: 3,9
E1: 3,4
G2: 4,5
G5: 5,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
H4,I4: 1.. / H4 = 1  =>  4 pairs (_) / I4 = 1  =>  0 pairs (X)
A8,B8: 1.. / A8 = 1  =>  6 pairs (_) / B8 = 1  =>  4 pairs (_)
B2,B8: 1.. / B2 = 1  =>  6 pairs (_) / B8 = 1  =>  4 pairs (_)
H1,H4: 1.. / H1 = 1  =>  0 pairs (X) / H4 = 1  =>  4 pairs (_)
D3,E3: 2.. / D3 = 2  =>  4 pairs (_) / E3 = 2  =>  0 pairs (X)
I4,G6: 2.. / I4 = 2  =>  6 pairs (_) / G6 = 2  =>  0 pairs (X)
I7,G8: 2.. / I7 = 2  =>  0 pairs (X) / G8 = 2  =>  6 pairs (_)
G6,G8: 2.. / G6 = 2  =>  0 pairs (X) / G8 = 2  =>  6 pairs (_)
I4,I7: 2.. / I4 = 2  =>  6 pairs (_) / I7 = 2  =>  0 pairs (X)
D8,F8: 3.. / D8 = 3  => 13 pairs (_) / F8 = 3  => 15 pairs (_)
G6,H6: 4.. / G6 = 4  => 17 pairs (_) / H6 = 4  => 11 pairs (_)
A2,B2: 6.. / A2 = 6  =>  5 pairs (_) / B2 = 6  =>  5 pairs (_)
E4,E6: 6.. / E4 = 6  =>  6 pairs (_) / E6 = 6  =>  4 pairs (_)
B5,H5: 6.. / B5 = 6  => 15 pairs (_) / H5 = 6  =>  4 pairs (_)
D6,D8: 7.. / D6 = 7  =>  4 pairs (_) / D8 = 7  =>  0 pairs (X)
E2,E3: 8.. / E2 = 8  =>  5 pairs (_) / E3 = 8  => 17 pairs (_)
B5,C5: 8.. / B5 = 8  =>  4 pairs (_) / C5 = 8  =>  9 pairs (_)
F8,F9: 8.. / F8 = 8  => 16 pairs (_) / F9 = 8  =>  5 pairs (_)
H1,H3: 9.. / H1 = 9  => 15 pairs (_) / H3 = 9  =>  4 pairs (_)
F5,F6: 9.. / F5 = 9  =>  4 pairs (_) / F6 = 9  =>  7 pairs (_)
A7,B7: 9.. / A7 = 9  =>  4 pairs (_) / B7 = 9  =>  4 pairs (_)
* DURATION: 0:00:24.867761  START: 00:38:33.273881  END: 00:38:58.141642 2017-05-04
* CP COUNT: (21)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (D1,E1,G2,G5)
* .52..68.......7.2......16....48..9..2..41......1.....8..61..38.....9...63..6..1.9
* PAIR D1: 3,9 BLK 2
D2: 3,9,5                                # reduction candidate for 3,9
D2: 3,9                                  # 15 pairs
D3: 3,9,2,5                              # reduction candidate for 3,9
D3: 3,9 => CTR
* .52.468.....58742.....216....48..9.22..41......12...48..61..384...7932563..65.1.9
D3: 2,5                                  #  5 pairs
* PAIR D1: 3,9 ROW 1
H1: 3,9,1,4,7                            # reduction candidate for 3,9
H1: 1,4,7                                # 10 pairs
H1: 3,9                                  #  6 pairs
* PAIR E1: 3,4 BLK 2
E2: 3,4,5,8                              # reduction candidate for 3,4
E2: 3,4                                  # 17 pairs
E3: 3,4,2,5,8                            # reduction candidate for 3,4
E3: 3,4 => SOLVED
* 152946837963587421847231695574863912289415763631729548796152384415398276328674159
E3: 2,5,8                                #  4 pairs
* PAIR E1: 3,4 ROW 1
H1: 3,4,1,7,9                            # reduction candidate for 3,4
H1: 3,4                                  #  8 pairs
I1: 3,4,1,7                              # reduction candidate for 3,4
I1: 3,4                                  # 13 pairs
* PAIR G2: 4,5 BLK 3
I2: 4,5,1,3                              # reduction candidate for 4,5
I2: 4,5                                  # 20 pairs
H3: 4,5,3,7,9                            # reduction candidate for 4,5
H3: 4,5 => CTR
* .5234689......7.2......16....48..91.2..41......1.....8..61.438.....93..63..6.81.9
H3: 3,7,9                                #  4 pairs
I3: 4,5,3,7                              # reduction candidate for 4,5
I3: 4,5                                  #  6 pairs
* PAIR G2: 4,5 ROW 2
E2: 4,5,3,8                              # reduction candidate for 4,5
E2: 4,5 => CTR
* 152.468.7....57421...2816.5..48..9122..41..63..1....48..61..384.1..932.63..6..1.9
E2: 3,8                                  #  5 pairs
* PAIR G2: 4,5 COL G
G6: 4,5,2,7                              # reduction candidate for 4,5
G6: 4,5                                  #  6 pairs
G8: 4,5,2,7                              # reduction candidate for 4,5
G8: 4,5 => CTR
* .52.468...1..875244..2516....48.29.52.54197.39.17..248596174382.2.593476347628159
G8: 2,7                                  #  5 pairs
* PAIR G5: 5,7 BLK 6
H4: 5,7,1,3,6                            # reduction candidate for 5,7
H4: 5,7 => CTR
* .52..681......7.2......169...48..9.12..41......1...248..61..382....9.4.63..6..1.9
H4: 1,3,6                                #  4 pairs
I4: 5,7,1,2,3                            # reduction candidate for 5,7
I4: 5,7 => CTR
* .52.468...1..875244..2516.7.7483291528.41.763..17..248596174382.2.593476347628159
I4: 1,2,3                                #  4 pairs
H5: 5,7,3,6                              # reduction candidate for 5,7
H5: 5,7 => CTR
* .52.468..61..875244..2516...34865912268419753591732468926174385..7593246345628179
H5: 3,6                                  #  5 pairs
I5: 5,7,3                                # reduction candidate for 5,7
I5: 5,7                                  #  8 pairs
G6: 5,7,2,4                              # reduction candidate for 5,7
G6: 5,7                                  # 13 pairs
H6: 5,7,3,4,6                            # reduction candidate for 5,7
H6: 5,7 => CTR
* .52.468......8752......16....48..9122..41.763..17.2458..61.4385...5932.63.56.81.9
H6: 3,4,6                                #  4 pairs
* PAIR G5: 5,7 ROW 5
C5: 5,7,3,8,9                            # reduction candidate for 5,7
C5: 5,7                                  # 13 pairs
C5: 3,8,9                                #  4 pairs
* PAIR G5: 5,7 COL G
G8: 5,7,2,4                              # reduction candidate for 5,7
G8: 5,7 => CTR
* .52..68.......7.2......16....48..9..2..41......1...248..61..38.....9...63..6..1.9
G8: 2,4                                  #  6 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top95-075-base-pr-000.dot
* REASONING
* DIS # D3: 3,9 => CTR => D3: 2,5
* PRF # E3: 3,4 => SOL
* DIS # H3: 4,5 => CTR => H3: 3,7,9
* DIS # E2: 4,5 => CTR => E2: 3,8
* DIS # G8: 4,5 => CTR => G8: 2,7
* DIS # H4: 5,7 => CTR => H4: 1,3,6
* DIS # I4: 5,7 => CTR => I4: 1,2,3
* DIS # H5: 5,7 => CTR => H5: 3,6
* DIS # H6: 5,7 => CTR => H6: 3,4,6
* DIS # G8: 5,7 => CTR => G8: 2,4
* CNT  10 HDP CHAINS /  33 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (D1,E1,G2,G5)
* .52..68.......7.2......16....48..9..2..41......1.....8..61..38.....9...63..6..1.9
* PAIR D1: 3,9 BLK 2
D2: 3,9,5                                # reduction candidate for 3,9
D2: 3,9                                  # 15 pairs
D3: 3,9,2,5                              # reduction candidate for 3,9
D3: 3,9 => CTR
* .52.468.....58742.....216....48..9.22..41......12...48..61..384...7932563..65.1.9
* RESTART
* PAIR D1: 3,9 BLK 2
D2: 3,9,5                                # reduction candidate for 3,9
D2: 3,9                                  # 15 pairs
D2: 5                                    # 13 pairs
* PAIR D1: 3,9 ROW 1
H1: 3,9,1,4,7                            # reduction candidate for 3,9
H1: 1,4,7                                # 11 pairs
H1: 3,9                                  #  7 pairs
* PAIR E1: 3,4 BLK 2
E2: 3,4,5,8                              # reduction candidate for 3,4
E2: 3,4                                  # 17 pairs
E3: 3,4,2,5,8                            # reduction candidate for 3,4
E3: 3,4 => SOLVED
* 152946837963587421847231695574863912289415763631729548796152384415398276328674159
* DURATION: 0:00:07.893919  START: 00:39:20.764544  END: 00:39:28.658463 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top95-075-base-pr-001.dot
* REASONING
* DIS # D3: 3,9 => CTR => D3: 2,5
* PRF D3: 2,5 # E3: 3,4 => SOL
* STA D3: 2,5 + E3: 3,4
* CNT   2 HDP CHAINS /   8 HYP OPENED

Header Info

Top 95 Sudokus 075
[sudoku:top95] “95 Hard Puzzles”, http://magictour.free.fr/top95, or http://norvig.com/top95.txt

Solution

position: 152946837963587421847231695574863912289415763631729548796152384415398276328674159 solved
Solution

See section Pair Reduction for the HDP chains leading to this result.

Appendix: Full HDP Chains

A1. Pair Reduction Analysis

Full list of HDP chains traversed:

* INC # D2: 3,9 => UNS
* DIS # D3: 3,9 => CTR => D3: 2,5
* INC # D3: 2,5 => UNS
* INC # H1: 3,9 => UNS
* INC # H1: 1,4,7 => UNS
* INC # E2: 3,4 => UNS
* PRF # E3: 3,4 => SOL
* INC # E3: 2,5,8 => UNS
* INC # H1: 3,4 => UNS
* INC # I1: 3,4 => UNS
* INC # I2: 4,5 => UNS
* DIS # H3: 4,5 => CTR => H3: 3,7,9
* INC # H3: 3,7,9 => UNS
* INC # I3: 4,5 => UNS
* DIS # E2: 4,5 => CTR => E2: 3,8
* INC # E2: 3,8 => UNS
* INC # G6: 4,5 => UNS
* DIS # G8: 4,5 => CTR => G8: 2,7
* INC # G8: 2,7 => UNS
* DIS # H4: 5,7 => CTR => H4: 1,3,6
* INC # H4: 1,3,6 => UNS
* DIS # I4: 5,7 => CTR => I4: 1,2,3
* INC # I4: 1,2,3 => UNS
* DIS # H5: 5,7 => CTR => H5: 3,6
* INC # H5: 3,6 => UNS
* INC # I5: 5,7 => UNS
* INC # G6: 5,7 => UNS
* DIS # H6: 5,7 => CTR => H6: 3,4,6
* INC # H6: 3,4,6 => UNS
* INC # C5: 5,7 => UNS
* INC # C5: 3,8,9 => UNS
* DIS # G8: 5,7 => CTR => G8: 2,4
* INC # G8: 2,4 => UNS
* CNT  33 HDP CHAINS /  33 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # D2: 3,9 => UNS
* DIS # D3: 3,9 => CTR => D3: 2,5
* INC D3: 2,5 # D2: 3,9 => UNS
* INC D3: 2,5 # D2: 5 => UNS
* INC D3: 2,5 # H1: 3,9 => UNS
* INC D3: 2,5 # H1: 1,4,7 => UNS
* INC D3: 2,5 # E2: 3,4 => UNS
* PRF D3: 2,5 # E3: 3,4 => SOL
* STA D3: 2,5 + E3: 3,4
* CNT   8 HDP CHAINS /   8 HYP OPENED