Analysis of xx-top500-419-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .543.........6..7..........76..2.......5..3.81..........24..........35.........6. initial

Autosolve

position: .543.7.......6..7..76.4....763.2......9576318185934.2.6.245......76.35.25..7.2.6. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A2: 2,8 => CTR => A2: 3,9
* DIS # G1: 8,9 => CTR => G1: 1,2,6
* DIS # H3: 8,9 => CTR => H3: 3,5
* DIS # A1: 8,9 => CTR => A1: 2
* DIS # F3: 1,8 => CTR => F3: 5,9
* PRF # G9: 4,9 => SOL
* DIS # E9: 1,8 => CTR => E9: 9
* CNT   7 HDP CHAINS /  29 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 # A2: 2,8 => CTR => A2: 3,9
* DIS A2: 3,9 # G1: 8,9 => CTR => G1: 1,2,6
* DIS A2: 3,9 + G1: 1,2,6 # H3: 8,9 => CTR => H3: 3,5
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 # A1: 8,9 => CTR => A1: 2
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 # E1: 1 => CTR => E1: 8,9
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 # G3: 8,9 => CTR => G3: 2
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 + G3: 2 # G2: 4 => CTR => G2: 8,9
* PRF A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 + G3: 2 + G2: 8,9 # H8: 8,9 => SOL
* STA A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 + G3: 2 + G2: 8,9 + H8: 8,9
* CNT   8 HDP CHAINS /  26 HYP OPENED

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

Details

Positions

.543.........6..7..........76..2.......5..3.81..........24..........35.........6. initial
.543.7.......6..7..76.4....763.2......9576318185934.2.6.245......76.35.25..7.2.6. autosolve
254387196391265874876149253763821945429576318185934627612458739947613582538792461 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (11)
C2: 1,8
D2: 2,8
H1: 8,9
A5: 2,4
B5: 2,4
D4: 1,8
F4: 1,8
G4: 4,9
G6: 6,7
I6: 6,7
C9: 1,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B2,C2: 1.. / B2 = 1  =>  0 pairs (X) / C2 = 1  => 12 pairs (_)
D4,F4: 1.. / D4 = 1  => 14 pairs (_) / F4 = 1  => 12 pairs (_)
B8,E8: 1.. / B8 = 1  => 14 pairs (_) / E8 = 1  => 17 pairs (_)
C2,C9: 1.. / C2 = 1  => 12 pairs (_) / C9 = 1  =>  0 pairs (X)
D3,D4: 1.. / D3 = 1  => 12 pairs (_) / D4 = 1  => 14 pairs (_)
D2,D3: 2.. / D2 = 2  => 11 pairs (_) / D3 = 2  => 14 pairs (_)
A5,B5: 2.. / A5 = 2  =>  0 pairs (X) / B5 = 2  => 11 pairs (_)
A1,G1: 2.. / A1 = 2  => 11 pairs (_) / G1 = 2  =>  0 pairs (X)
B2,B5: 2.. / B2 = 2  =>  0 pairs (X) / B5 = 2  => 11 pairs (_)
A2,A3: 3.. / A2 = 3  => 11 pairs (_) / A3 = 3  =>  0 pairs (X)
B7,B9: 3.. / B7 = 3  => 15 pairs (_) / B9 = 3  => 12 pairs (_)
A2,I2: 3.. / A2 = 3  => 11 pairs (_) / I2 = 3  =>  0 pairs (X)
B9,I9: 3.. / B9 = 3  => 12 pairs (_) / I9 = 3  => 15 pairs (_)
H3,H7: 3.. / H3 = 3  => 15 pairs (_) / H7 = 3  => 12 pairs (_)
G2,I2: 4.. / G2 = 4  => 20 pairs (_) / I2 = 4  => 14 pairs (_)
A5,B5: 4.. / A5 = 4  => 11 pairs (_) / B5 = 4  =>  0 pairs (X)
A5,A8: 4.. / A5 = 4  => 11 pairs (_) / A8 = 4  =>  0 pairs (X)
H4,H8: 4.. / H4 = 4  => 12 pairs (_) / H8 = 4  => 15 pairs (_)
F2,F3: 5.. / F2 = 5  => 11 pairs (_) / F3 = 5  =>  0 pairs (X)
H4,I4: 5.. / H4 = 5  => 15 pairs (_) / I4 = 5  => 12 pairs (_)
F2,I2: 5.. / F2 = 5  => 11 pairs (_) / I2 = 5  =>  0 pairs (X)
H3,H4: 5.. / H3 = 5  => 12 pairs (_) / H4 = 5  => 15 pairs (_)
G1,I1: 6.. / G1 = 6  => 10 pairs (_) / I1 = 6  =>  9 pairs (_)
G6,I6: 6.. / G6 = 6  =>  9 pairs (_) / I6 = 6  => 10 pairs (_)
G1,G6: 6.. / G1 = 6  => 10 pairs (_) / G6 = 6  =>  9 pairs (_)
I1,I6: 6.. / I1 = 6  =>  9 pairs (_) / I6 = 6  => 10 pairs (_)
G6,I6: 7.. / G6 = 7  => 10 pairs (_) / I6 = 7  =>  9 pairs (_)
G7,I7: 7.. / G7 = 7  =>  9 pairs (_) / I7 = 7  => 10 pairs (_)
G6,G7: 7.. / G6 = 7  => 10 pairs (_) / G7 = 7  =>  9 pairs (_)
I6,I7: 7.. / I6 = 7  =>  9 pairs (_) / I7 = 7  => 10 pairs (_)
D4,F4: 8.. / D4 = 8  => 12 pairs (_) / F4 = 8  => 14 pairs (_)
A8,C9: 8.. / A8 = 8  =>  0 pairs (X) / C9 = 8  => 12 pairs (_)
C2,C9: 8.. / C2 = 8  =>  0 pairs (X) / C9 = 8  => 12 pairs (_)
* DURATION: 0:00:51.230713  START: 17:08:52.822707  END: 17:09:44.053420 2017-05-04
* CP COUNT: (33)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,B5,C2,C9,D2,D4,F4,G4,G6,H1,I6)
* .543.7.......6..7..76.4....763.2......9576318185934.2.6.245......76.35.25..7.2.6.
* PAIR D2: 2,8 BLK 2
D3: 2,8,1                                # reduction candidate for 2,8
D3: 2,8                                  # 14 pairs
D3: 1                                    # 12 pairs
* PAIR D2: 2,8 ROW 2
A2: 2,8,3,9                              # reduction candidate for 2,8
A2: 2,8 => CTR
* .54387.91.91.65473376.4....763.2.945.29576318185934.2.61245..3.947613582538792164
A2: 3,9                                  # 12 pairs
G2: 2,8,4,9                              # reduction candidate for 2,8
G2: 2,8                                  # 18 pairs
* PAIR H1: 8,9 BLK 3
G1: 8,9,1,2,6                            # reduction candidate for 8,9
G1: 8,9 => CTR
* 25431789639186527..76.4....763128...4295763181859346276.245178..176.3542548792163
G1: 1,2,6                                # 11 pairs
G2: 8,9,2,4                              # reduction candidate for 8,9
G2: 8,9                                  # 17 pairs
G3: 8,9,1,2                              # reduction candidate for 8,9
G3: 8,9                                  # 15 pairs
H3: 8,9,3,5                              # reduction candidate for 8,9
H3: 8,9 => CTR
* .543.7.......6..7..76.4....763.2..5...9576318185934.2.6.245..3...76.35425..7.2.6.
H3: 3,5                                  # 12 pairs
* PAIR H1: 8,9 ROW 1
A1: 8,9,2                                # reduction candidate for 8,9
A1: 8,9 => CTR
* 854317296391265.7..76.4..3.763128954..95763181859346276.2451789917683542548792163
A1: 2                                    # 11 pairs
E1: 8,9,1                                # reduction candidate for 8,9
E1: 8,9                                  # 15 pairs
* PAIR H1: 8,9 COL H
H7: 8,9,3                                # reduction candidate for 8,9
H7: 8,9                                  # 15 pairs
H8: 8,9,4                                # reduction candidate for 8,9
H8: 8,9                                  # 12 pairs
* PAIR D4: 1,8 COL D
D3: 1,8,2                                # reduction candidate for 1,8
D3: 2                                    # 14 pairs
D3: 1,8                                  # 11 pairs
* PAIR F4: 1,8 COL F
F3: 1,8,5,9                              # reduction candidate for 1,8
F3: 1,8 => CTR
* 254397.8.....65.7..76.4....763.2....429576318185934726612459837.4761359253.7.2.6.
F3: 5,9                                  # 12 pairs
F7: 1,8,9                                # reduction candidate for 1,8
F7: 1,8                                  # 15 pairs
* PAIR G4: 4,9 BLK 6
H4: 4,9,5                                # reduction candidate for 4,9
H4: 4,9                                  # 12 pairs
I4: 4,9,5                                # reduction candidate for 4,9
I4: 4,9                                  # 15 pairs
* PAIR G4: 4,9 COL G
G2: 4,9,2,8                              # reduction candidate for 4,9
G2: 4,9                                  # 20 pairs
G9: 4,9,1,8                              # reduction candidate for 4,9
G9: 4,9 => SOLVED
* 254387196391265874876149253763821945429576318185934627612458739947613582538792461
G9: 1,8                                  # 19 pairs
* PAIR C9: 1,8 ROW 9
E9: 1,8,9                                # reduction candidate for 1,8
E9: 1,8 => CTR
* .54397.8.391865274876241...763.2.....29576318185934.2.6.245....9.76.35.25.8712.6.
E9: 9                                    # 16 pairs
G9: 1,8,4,9                              # reduction candidate for 1,8
G9: 1,8                                  # 19 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-419-base-pr-000.dot
* REASONING
* DIS # A2: 2,8 => CTR => A2: 3,9
* DIS # G1: 8,9 => CTR => G1: 1,2,6
* DIS # H3: 8,9 => CTR => H3: 3,5
* DIS # A1: 8,9 => CTR => A1: 2
* DIS # F3: 1,8 => CTR => F3: 5,9
* PRF # G9: 4,9 => SOL
* DIS # E9: 1,8 => CTR => E9: 9
* CNT   7 HDP CHAINS /  29 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,B5,C2,C9,D2,D4,F4,G4,G6,H1,I6)
* .543.7.......6..7..76.4....763.2......9576318185934.2.6.245......76.35.25..7.2.6.
* PAIR D2: 2,8 BLK 2
D3: 2,8,1                                # reduction candidate for 2,8
D3: 2,8                                  # 14 pairs
D3: 1                                    # 12 pairs
* PAIR D2: 2,8 ROW 2
A2: 2,8,3,9                              # reduction candidate for 2,8
A2: 2,8 => CTR
* .54387.91.91.65473376.4....763.2.945.29576318185934.2.61245..3.947613582538792164
G2: 2,8,4,9                              # reduction candidate for 2,8
G2: 2,8                                  # 18 pairs
* RESTART
* PAIR D2: 2,8 ROW 2
G2: 2,8,4,9                              # reduction candidate for 2,8
G2: 4,9                                  # 23 pairs
G2: 2,8                                  # 18 pairs
* PAIR RESTART
* PAIR D2: 2,8 BLK 2
D3: 2,8,1                                # reduction candidate for 2,8
D3: 2,8                                  # 15 pairs
D3: 1                                    # 13 pairs
* PAIR D2: 2,8 ROW 2
G2: 2,8,4,9                              # reduction candidate for 2,8
G2: 4,9                                  # 23 pairs
G2: 2,8                                  # 18 pairs
* PAIR H1: 8,9 BLK 3
G1: 8,9,1,2,6                            # reduction candidate for 8,9
G1: 8,9 => CTR
* 25431789639186527..76.4....763128...4295763181859346276.245178..176.3542548792163
G2: 8,9,2,4                              # reduction candidate for 8,9
G2: 8,9                                  # 17 pairs
G3: 8,9,1,2                              # reduction candidate for 8,9
G3: 8,9                                  # 16 pairs
H3: 8,9,3,5                              # reduction candidate for 8,9
H3: 8,9 => CTR
* .543.7.......6..7..76.4....763.2..5...9576318185934.2.6.245..3...76.35425..7.2.6.
* PAIR H1: 8,9 ROW 1
A1: 8,9,2                                # reduction candidate for 8,9
A1: 8,9 => CTR
* 854317296391265.7..76.4..3.763128954..95763181859346276.2451789917683542548792163
E1: 8,9,1                                # reduction candidate for 8,9
E1: 8,9                                  # 17 pairs
* RESTART
* PAIR H1: 8,9 ROW 1
E1: 8,9,1                                # reduction candidate for 8,9
E1: 1 => CTR
* 25431768939186527..76.4....763128...4295763181859347266.24518.7.176.3542548792163
* PAIR H1: 8,9 COL H
H7: 8,9,3                                # reduction candidate for 8,9
H7: 8,9                                  # 24 pairs
H8: 8,9,4                                # reduction candidate for 8,9
H8: 8,9                                  # 20 pairs
* PAIR RESTART
* PAIR H1: 8,9 BLK 3
G2: 8,9,2,4                              # reduction candidate for 8,9
G2: 8,9                                  # 20 pairs
G3: 8,9,2                                # reduction candidate for 8,9
G3: 8,9 => CTR
* 254397.8.3918652748762419..7631284..429576318185934.2.6.24598379.76.35.25..7.2.6.
* RESTART
* PAIR H1: 8,9 BLK 3
G2: 8,9,4                                # reduction candidate for 8,9
G2: 4 => CTR
* 254397.8....26.47..76.4.2..763.2.9..429576318185934.2.6.2459837..76.35925..7.2.6.
* PAIR H1: 8,9 COL H
H7: 8,9,3                                # reduction candidate for 8,9
H7: 8,9                                  # 22 pairs
H8: 8,9,4                                # reduction candidate for 8,9
H8: 8,9 => SOLVED
* 254387196391265874876149253763821945429576318185934627612458739947613582538792461
* DURATION: 0:00:27.483975  START: 17:10:09.955865  END: 17:10:37.439840 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-419-base-pr-001.dot
* REASONING
* DIS # A2: 2,8 => CTR => A2: 3,9
* DIS A2: 3,9 # G1: 8,9 => CTR => G1: 1,2,6
* DIS A2: 3,9 + G1: 1,2,6 # H3: 8,9 => CTR => H3: 3,5
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 # A1: 8,9 => CTR => A1: 2
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 # E1: 1 => CTR => E1: 8,9
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 # G3: 8,9 => CTR => G3: 2
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 + G3: 2 # G2: 4 => CTR => G2: 8,9
* PRF A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 + G3: 2 + G2: 8,9 # H8: 8,9 => SOL
* STA A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 + G3: 2 + G2: 8,9 + H8: 8,9
* CNT   8 HDP CHAINS /  26 HYP OPENED

Header Info

Top 500 Minimum 17 419

solution: 254387196391265874876149253763821945429576318185934627612458739947613582538792461
info: 95092    FNBHXYK  S8.f     40995

http://www.sfsudoku.com/su17ExtremeDiff500.txt from http://www.minimumsudoku.com/

Solution

position: 254387196391265874876149253763821945429576318185934627612458739947613582538792461 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 # D3: 2,8 => UNS
* INC # D3: 1 => UNS
* DIS # A2: 2,8 => CTR => A2: 3,9
* INC # A2: 3,9 => UNS
* INC # G2: 2,8 => UNS
* DIS # G1: 8,9 => CTR => G1: 1,2,6
* INC # G1: 1,2,6 => UNS
* INC # G2: 8,9 => UNS
* INC # G3: 8,9 => UNS
* DIS # H3: 8,9 => CTR => H3: 3,5
* INC # H3: 3,5 => UNS
* DIS # A1: 8,9 => CTR => A1: 2
* INC # A1: 2 => UNS
* INC # E1: 8,9 => UNS
* INC # H7: 8,9 => UNS
* INC # H8: 8,9 => UNS
* INC # D3: 1,8 => UNS
* INC # D3: 2 => UNS
* DIS # F3: 1,8 => CTR => F3: 5,9
* INC # F3: 5,9 => UNS
* INC # F7: 1,8 => UNS
* INC # H4: 4,9 => UNS
* INC # I4: 4,9 => UNS
* INC # G2: 4,9 => UNS
* PRF # G9: 4,9 => SOL
* INC # G9: 1,8 => UNS
* DIS # E9: 1,8 => CTR => E9: 9
* INC # E9: 9 => UNS
* INC # G9: 1,8 => UNS
* CNT  29 HDP CHAINS /  29 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # D3: 2,8 => UNS
* INC # D3: 1 => UNS
* DIS # A2: 2,8 => CTR => A2: 3,9
* INC A2: 3,9 # G2: 2,8 => UNS
* INC A2: 3,9 # G2: 2,8 => UNS
* INC A2: 3,9 # G2: 4,9 => UNS
* INC A2: 3,9 # D3: 2,8 => UNS
* INC A2: 3,9 # D3: 1 => UNS
* INC A2: 3,9 # G2: 2,8 => UNS
* INC A2: 3,9 # G2: 4,9 => UNS
* DIS A2: 3,9 # G1: 8,9 => CTR => G1: 1,2,6
* INC A2: 3,9 + G1: 1,2,6 # G2: 8,9 => UNS
* INC A2: 3,9 + G1: 1,2,6 # G3: 8,9 => UNS
* DIS A2: 3,9 + G1: 1,2,6 # H3: 8,9 => CTR => H3: 3,5
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 # A1: 8,9 => CTR => A1: 2
* INC A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 # E1: 8,9 => UNS
* INC A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 # E1: 8,9 => UNS
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 # E1: 1 => CTR => E1: 8,9
* INC A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 # H7: 8,9 => UNS
* INC A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 # H8: 8,9 => UNS
* INC A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 # G2: 8,9 => UNS
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 # G3: 8,9 => CTR => G3: 2
* INC A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 + G3: 2 # G2: 8,9 => UNS
* DIS A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 + G3: 2 # G2: 4 => CTR => G2: 8,9
* INC A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 + G3: 2 + G2: 8,9 # H7: 8,9 => UNS
* PRF A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 + G3: 2 + G2: 8,9 # H8: 8,9 => SOL
* STA A2: 3,9 + G1: 1,2,6 + H3: 3,5 + A1: 2 + E1: 8,9 + G3: 2 + G2: 8,9 + H8: 8,9
* CNT  26 HDP CHAINS /  26 HYP OPENED