Analysis of xx-top500-485-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .2.97........8..1.......3.....5..2..7.1......84.......9.......71......8....3..... initial

Autosolve

position: .2.971.......83.12.1....3.....5..2..751......842......9......271......832..3..... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A1: 4,6 => CTR => A1: 3,5
* PRF # A2: 4,6 => SOL
* PRF # A2: 4,6 => SOL
* DIS # G2: 4,6 => CTR => G2: 5,7,9
* DIS # D5: 4,6 => CTR => D5: 2,8
* DIS # D7: 4,6 => CTR => D7: 1,8
* DIS # D8: 4,6 => CTR => D8: 2,7
* DIS # G2: 7,9 => CTR => G2: 4,5,6
* PRF # G2: 4,5,6 => SOL
* DIS # C3: 7,9 => CTR => C3: 8
* PRF # C3: 8 => SOL
* DIS # H6: 7,9 => CTR => H6: 3,5,6
* PRF # C3: 8,9 => SOL
* DIS # C3: 7 => CTR => C3: 8,9
* DIS # I5: 8,9 => CTR => I5: 4,6
* PRF # A1: 4,5 => SOL
* DIS # I4: 1,4 => CTR => I4: 8
* PRF # I4: 8 => SOL
* PRF # F4: 4,7 => SOL
* DIS # F4: 8 => CTR => F4: 4,7
* DIS # C8: 6,7 => CTR => C8: 4,5
* DIS # B9: 6,7 => CTR => B9: 8
* DIS # F8: 6,7 => CTR => F8: 2,4,5,9
* CNT  23 HDP CHAINS /  50 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 # A1: 4,6 => CTR => A1: 3,5
* PRF A1: 3,5 # A2: 4,6 => SOL
* STA A1: 3,5 + A2: 4,6
* CNT   2 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

.2.97........8..1.......3.....5..2..7.1......84.......9.......71......8....3..... initial
.2.971.......83.12.1....3.....5..2..751......842......9......271......832..3..... autosolve
523971864679483512418265379396517248751824936842639751934158627165792483287346195 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
A3: 4,6
D2: 4,6
H3: 7,9
I3: 8,9
A4: 3,6
E4: 1,4
H4: 4,7
B8: 6,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E4,I4: 1.. / E4 = 1  =>  0 pairs (*) / I4 = 1  =>  0 pairs (X)
D6,D7: 1.. / D6 = 1  =>  0 pairs (X) / D7 = 1  =>  0 pairs (_)
A1,C1: 3.. / A1 = 3  =>  9 pairs (_) / C1 = 3  =>  0 pairs (*)
E5,E6: 3.. / E5 = 3  =>  8 pairs (_) / E6 = 3  =>  8 pairs (_)
H5,H6: 3.. / H5 = 3  =>  8 pairs (_) / H6 = 3  =>  8 pairs (_)
B7,C7: 3.. / B7 = 3  =>  9 pairs (_) / C7 = 3  => 15 pairs (_)
E5,H5: 3.. / E5 = 3  =>  8 pairs (_) / H5 = 3  =>  8 pairs (_)
E6,H6: 3.. / E6 = 3  =>  8 pairs (_) / H6 = 3  =>  8 pairs (_)
A1,A4: 3.. / A1 = 3  =>  9 pairs (_) / A4 = 3  =>  0 pairs (*)
B4,B7: 3.. / B4 = 3  => 15 pairs (_) / B7 = 3  =>  9 pairs (_)
A1,A2: 5.. / A1 = 5  =>  0 pairs (*) / A2 = 5  =>  0 pairs (X)
E3,F3: 5.. / E3 = 5  =>  8 pairs (_) / F3 = 5  =>  8 pairs (_)
A2,G2: 5.. / A2 = 5  =>  8 pairs (_) / G2 = 5  =>  0 pairs (*)
G2,H3: 7.. / G2 = 7  =>  0 pairs (X) / H3 = 7  =>  0 pairs (_)
C3,H3: 7.. / C3 = 7  =>  0 pairs (X) / H3 = 7  =>  0 pairs (_)
F4,H4: 7.. / F4 = 7  =>  0 pairs (*) / H4 = 7  =>  0 pairs (X)
D6,D8: 7.. / D6 = 7  =>  0 pairs (X) / D8 = 7  => 13 pairs (_)
G2,G6: 7.. / G2 = 7  =>  0 pairs (X) / G6 = 7  =>  0 pairs (_)
C1,C3: 8.. / C1 = 8  =>  0 pairs (X) / C3 = 8  =>  0 pairs (_)
B7,B9: 8.. / B7 = 8  =>  0 pairs (X) / B9 = 8  =>  9 pairs (_)
C3,I3: 8.. / C3 = 8  =>  0 pairs (*) / I3 = 8  =>  0 pairs (X)
F4,I4: 8.. / F4 = 8  =>  0 pairs (X) / I4 = 8  =>  0 pairs (_)
B9,F9: 8.. / B9 = 8  =>  9 pairs (_) / F9 = 8  =>  0 pairs (X)
D5,D7: 8.. / D5 = 8  =>  0 pairs (*) / D7 = 8  =>  0 pairs (X)
G1,G5: 8.. / G1 = 8  =>  0 pairs (*) / G5 = 8  =>  0 pairs (X)
B4,C4: 9.. / B4 = 9  => 10 pairs (_) / C4 = 9  => 13 pairs (_)
B2,B4: 9.. / B2 = 9  => 13 pairs (_) / B4 = 9  => 10 pairs (_)
* DURATION: 0:00:50.082082  START: 19:12:35.830520  END: 19:13:25.912602 2017-05-04
* CP COUNT: (27)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A4,B8,D2,E4,H3,H4,I3)
* .2.971.......83.12.1....3.....5..2..751......842......9......271......832..3.....
* PAIR A3: 4,6 BLK 1
A1: 4,6,3,5                              # reduction candidate for 4,6
A1: 4,6 => CTR
* .23971865579483.12.18...3793965172487518..93684263975193.1.8.2716.792.832873..19.
A1: 3,5                                  #  9 pairs
A2: 4,6,5                                # reduction candidate for 4,6
A2: 4,6 => SOLVED
* 523971864679483512418265379396517248751824936842639751934158627165792483287346195
A2: 5                                    #  8 pairs
* PAIR A3: 4,6 ROW 3
D3: 4,6,2                                # reduction candidate for 4,6
D3: 4,6                                  # 15 pairs
E3: 4,6,2,5                              # reduction candidate for 4,6
E3: 4,6                                  #  9 pairs
F3: 4,6,2,5                              # reduction candidate for 4,6
F3: 4,6                                  #  9 pairs
* PAIR D2: 4,6 BLK 2
D3: 4,6,2                                # reduction candidate for 4,6
D3: 4,6                                  # 15 pairs
E3: 4,6,2,5                              # reduction candidate for 4,6
E3: 4,6                                  #  9 pairs
F3: 4,6,2,5                              # reduction candidate for 4,6
F3: 4,6                                  #  9 pairs
* PAIR D2: 4,6 ROW 2
A2: 4,6,5                                # reduction candidate for 4,6
A2: 4,6 => SOLVED
* 523971864679483512418265379396517248751824936842639751934158627165792483287346195
A2: 5                                    #  8 pairs
G2: 4,6,5,7,9                            # reduction candidate for 4,6
G2: 4,6 => CTR
* .2.9718655.6483.12.18...379...5172487518..9368426397519..1...2716.792.832..3..19.
G2: 5,7,9                                # 10 pairs
* PAIR D2: 4,6 COL D
D5: 4,6,2,8                              # reduction candidate for 4,6
D5: 4,6 => CTR
* .2.971....7..83.12.1.2..37..9.54.2..751......8421.....9..8...271..7...832873.....
D5: 2,8                                  #  9 pairs
D7: 4,6,1,8                              # reduction candidate for 4,6
D7: 4,6 => CTR
* .2.971.......83.12.1....3.....5..2..7518.....8421.....9......271..7...832..3.....
D7: 1,8                                  #  9 pairs
D8: 4,6,2,7                              # reduction candidate for 4,6
D8: 4,6 => CTR
* .2.971.......83712.17...398...5.827.751...8..8427.....9831...271......832..3.....
D8: 2,7                                  #  9 pairs
* PAIR H3: 7,9 BLK 3
G2: 7,9,4,5,6                            # reduction candidate for 7,9
G2: 7,9 => CTR
* 328971...5..483712417...3986..5.827.751...8..8421.7...9..8...2717.....8328.3.....
G2: 4,5,6 => SOLVED
* 523971864679483512418265379396517248751824936842639751934158627165792483287346195
* PAIR H3: 7,9 ROW 3
C3: 7,9,8                                # reduction candidate for 7,9
C3: 7,9 => CTR
* 328971...5...83712417...3986..5.827.751...8..8421.7...9..8...2717.....8328.3.....
C3: 8 => SOLVED
* 523971864679483512418265379396517248751824936842639751934158627165792483287346195
* PAIR H3: 7,9 COL H
H6: 7,9,3,5,6                            # reduction candidate for 7,9
H6: 7,9 => CTR
* .2.9718......83.12.18...379...517248751....36842639...9......271..7...832..3.....
H6: 3,5,6                                #  8 pairs
* PAIR I3: 8,9 ROW 3
C3: 8,9,7                                # reduction candidate for 8,9
C3: 8,9 => SOLVED
* 523971864679483512418265379396517248751824936842639751934158627165792483287346195
C3: 7 => CTR
* .28971.......83.12.17...398...5.827.751...8..842......9..8...271......8328.3.7...
* PAIR I3: 8,9 COL I
I5: 8,9,4,6                              # reduction candidate for 8,9
I5: 8,9 => CTR
* .2.971.......83712.17...398...5.827.751...8.98421.7...9..8...2717.....8328.3.....
I5: 4,6                                  #  9 pairs
* PAIR A4: 3,6 BLK 4
B4: 3,6,9                                # reduction candidate for 3,6
B4: 3,6                                  # 13 pairs
C4: 3,6,9                                # reduction candidate for 3,6
C4: 3,6                                  # 10 pairs
* PAIR A4: 3,6 COL A
A1: 3,6,4,5                              # reduction candidate for 3,6
A1: 4,5 => SOLVED
* 523971864679483512418265379396517248751824936842639751934158627165792483287346195
A1: 3,6                                  #  8 pairs
* PAIR E4: 1,4 ROW 4
I4: 1,4,8                                # reduction candidate for 1,4
I4: 1,4 => CTR
* .2.971.......83712.17...398...5.827.751...8..8421.7...9..8...2717.....8328.3.....
I4: 8 => SOLVED
* 523971864679483512418265379396517248751824936842639751934158627165792483287346195
* PAIR E4: 1,4 COL E
E7: 1,4,5,6                              # reduction candidate for 1,4
E7: 1,4                                  #  9 pairs
E9: 1,4,5,6,9                            # reduction candidate for 1,4
E9: 1,4                                  # 10 pairs
* PAIR H4: 4,7 ROW 4
F4: 4,7,8                                # reduction candidate for 4,7
F4: 4,7 => SOLVED
* 523971864679483512418265379396517248751824936842639751934158627165792483287346195
F4: 8 => CTR
* .2.971.......83712.17...398...5.827.751...8..8421.7...9..8...2717.....8328.3.....
* PAIR B8: 6,7 BLK 7
C8: 6,7,4,5                              # reduction candidate for 6,7
C8: 6,7 => CTR
* .2.971.......83712.17...398...5.4271751......8427.....93.1.8.271......8328.3.7...
C8: 4,5                                  #  9 pairs
B9: 6,7,8                                # reduction candidate for 6,7
B9: 6,7 => CTR
* 3269718545974836124182..3796395172487518..9368426.97.19831...271..7...8327.3.81..
B9: 8                                    #  9 pairs
C9: 6,7,4,5                              # reduction candidate for 6,7
C9: 6,7                                  # 12 pairs
* PAIR B8: 6,7 ROW 8
D8: 6,7,2,4                              # reduction candidate for 6,7
D8: 6,7                                  # 10 pairs
F8: 6,7,2,4,5,9                          # reduction candidate for 6,7
F8: 6,7 => CTR
* .2.971.......83712.17...398...5.827.751...8..8427.....9831...271......832..3.....
F8: 2,4,5,9                              #  8 pairs
* PAIR B8: 6,7 COL B
B2: 6,7,9                                # reduction candidate for 6,7
B2: 9                                    # 13 pairs
B2: 6,7                                  # 10 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-485-base-pr-000.dot
* REASONING
* DIS # A1: 4,6 => CTR => A1: 3,5
* PRF # A2: 4,6 => SOL
* PRF # A2: 4,6 => SOL
* DIS # G2: 4,6 => CTR => G2: 5,7,9
* DIS # D5: 4,6 => CTR => D5: 2,8
* DIS # D7: 4,6 => CTR => D7: 1,8
* DIS # D8: 4,6 => CTR => D8: 2,7
* DIS # G2: 7,9 => CTR => G2: 4,5,6
* PRF # G2: 4,5,6 => SOL
* DIS # C3: 7,9 => CTR => C3: 8
* PRF # C3: 8 => SOL
* DIS # H6: 7,9 => CTR => H6: 3,5,6
* PRF # C3: 8,9 => SOL
* DIS # C3: 7 => CTR => C3: 8,9
* DIS # I5: 8,9 => CTR => I5: 4,6
* PRF # A1: 4,5 => SOL
* DIS # I4: 1,4 => CTR => I4: 8
* PRF # I4: 8 => SOL
* PRF # F4: 4,7 => SOL
* DIS # F4: 8 => CTR => F4: 4,7
* DIS # C8: 6,7 => CTR => C8: 4,5
* DIS # B9: 6,7 => CTR => B9: 8
* DIS # F8: 6,7 => CTR => F8: 2,4,5,9
* CNT  23 HDP CHAINS /  50 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A4,B8,D2,E4,H3,H4,I3)
* .2.971.......83.12.1....3.....5..2..751......842......9......271......832..3.....
* PAIR A3: 4,6 BLK 1
A1: 4,6,3,5                              # reduction candidate for 4,6
A1: 4,6 => CTR
* .23971865579483.12.18...3793965172487518..93684263975193.1.8.2716.792.832873..19.
A2: 4,6,5                                # reduction candidate for 4,6
A2: 4,6 => SOLVED
* 523971864679483512418265379396517248751824936842639751934158627165792483287346195
* DURATION: 0:00:04.027474  START: 19:14:15.062055  END: 19:14:19.089529 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-485-base-pr-001.dot
* REASONING
* DIS # A1: 4,6 => CTR => A1: 3,5
* PRF A1: 3,5 # A2: 4,6 => SOL
* STA A1: 3,5 + A2: 4,6
* CNT   2 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 485

solution: 523971864679483512418265379396517248751824936842639751934158627165792483287346195
info: 95984    FNBHWXYK S8.f     41704

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

Solution

position: 523971864679483512418265379396517248751824936842639751934158627165792483287346195 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:

* DIS # A1: 4,6 => CTR => A1: 3,5
* INC # A1: 3,5 => UNS
* PRF # A2: 4,6 => SOL
* INC # A2: 5 => UNS
* INC # D3: 4,6 => UNS
* INC # E3: 4,6 => UNS
* INC # F3: 4,6 => UNS
* INC # D3: 4,6 => UNS
* INC # E3: 4,6 => UNS
* INC # F3: 4,6 => UNS
* PRF # A2: 4,6 => SOL
* INC # A2: 5 => UNS
* DIS # G2: 4,6 => CTR => G2: 5,7,9
* INC # G2: 5,7,9 => UNS
* DIS # D5: 4,6 => CTR => D5: 2,8
* INC # D5: 2,8 => UNS
* DIS # D7: 4,6 => CTR => D7: 1,8
* INC # D7: 1,8 => UNS
* DIS # D8: 4,6 => CTR => D8: 2,7
* INC # D8: 2,7 => UNS
* DIS # G2: 7,9 => CTR => G2: 4,5,6
* PRF # G2: 4,5,6 => SOL
* DIS # C3: 7,9 => CTR => C3: 8
* PRF # C3: 8 => SOL
* DIS # H6: 7,9 => CTR => H6: 3,5,6
* INC # H6: 3,5,6 => UNS
* PRF # C3: 8,9 => SOL
* DIS # C3: 7 => CTR => C3: 8,9
* DIS # I5: 8,9 => CTR => I5: 4,6
* INC # I5: 4,6 => UNS
* INC # B4: 3,6 => UNS
* INC # C4: 3,6 => UNS
* INC # A1: 3,6 => UNS
* PRF # A1: 4,5 => SOL
* DIS # I4: 1,4 => CTR => I4: 8
* PRF # I4: 8 => SOL
* INC # E7: 1,4 => UNS
* INC # E9: 1,4 => UNS
* PRF # F4: 4,7 => SOL
* DIS # F4: 8 => CTR => F4: 4,7
* DIS # C8: 6,7 => CTR => C8: 4,5
* INC # C8: 4,5 => UNS
* DIS # B9: 6,7 => CTR => B9: 8
* INC # B9: 8 => UNS
* INC # C9: 6,7 => UNS
* INC # D8: 6,7 => UNS
* DIS # F8: 6,7 => CTR => F8: 2,4,5,9
* INC # F8: 2,4,5,9 => UNS
* INC # B2: 6,7 => UNS
* INC # B2: 9 => UNS
* CNT  50 HDP CHAINS /  50 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # A1: 4,6 => CTR => A1: 3,5
* PRF A1: 3,5 # A2: 4,6 => SOL
* STA A1: 3,5 + A2: 4,6
* CNT   2 HDP CHAINS /   2 HYP OPENED