Analysis of xx-top500-068-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....182...4.....7......3....6.4....53.....1...........8.1...3.....65..4.......... initial

Autosolve

position: 6...18234.43...871.18.4365916.432.853248.51...8.1..423851..43...32651.484.638.512 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # E2: 6,9 => CTR => E2: 2
* PRF # F6: 6,9 => SOL
* DIS # F6: 7 => CTR => F6: 6,9
* DIS # E6: 7,9 => CTR => E6: 6
* DIS # E7: 2 => CTR => E7: 7,9
* PRF # E7: 2,9 => SOL
* DIS # E7: 7 => CTR => E7: 2,9
* DIS # E7: 2 => CTR => E7: 7,9
* DIS # F6: 6 => CTR => F6: 7,9
* CNT   9 HDP CHAINS /  27 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 # E2: 6,9 => CTR => E2: 2
* PRF E2: 2 # C6: 7,9 => SOL
* STA E2: 2 + C6: 7,9
* CNT   2 HDP CHAINS /   7 HYP OPENED

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

Details

Positions

....182...4.....7......3....6.4....53.....1...........8.1...3.....65..4.......... initial
6...18234.43...871.18.4365916.432.853248.51...8.1..423851..43...32651.484.638.512 autosolve
675918234943526871218743659169432785324875196587169423851294367732651948496387512 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (16)
B1: 7,9
A3: 2,7
F2: 6,9
D3: 2,7
C4: 7,9
E5: 7,9
G4: 7,9
H5: 6,9
I5: 6,7
A8: 7,9
B9: 7,9
D7: 2,9
F9: 7,9
H7: 6,9
I7: 6,7
G8: 7,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A2,A3: 2.. / A2 = 2  =>  0 pairs (X) / A3 = 2  => 16 pairs (_)
D7,E7: 2.. / D7 = 2  => 17 pairs (_) / E7 = 2  =>  0 pairs (X)
A3,D3: 2.. / A3 = 2  => 16 pairs (_) / D3 = 2  =>  0 pairs (X)
E2,E7: 2.. / E2 = 2  => 17 pairs (_) / E7 = 2  =>  0 pairs (X)
C1,A2: 5.. / C1 = 5  => 19 pairs (_) / A2 = 5  => 17 pairs (_)
D1,D2: 5.. / D1 = 5  => 17 pairs (_) / D2 = 5  => 19 pairs (_)
A6,C6: 5.. / A6 = 5  => 19 pairs (_) / C6 = 5  => 17 pairs (_)
C1,D1: 5.. / C1 = 5  => 19 pairs (_) / D1 = 5  => 17 pairs (_)
A2,D2: 5.. / A2 = 5  => 17 pairs (_) / D2 = 5  => 19 pairs (_)
A2,A6: 5.. / A2 = 5  => 17 pairs (_) / A6 = 5  => 19 pairs (_)
C1,C6: 5.. / C1 = 5  => 19 pairs (_) / C6 = 5  => 17 pairs (_)
E2,F2: 6.. / E2 = 6  =>  0 pairs (X) / F2 = 6  => 17 pairs (_)
E6,F6: 6.. / E6 = 6  => 17 pairs (_) / F6 = 6  =>  0 pairs (X)
H5,I5: 6.. / H5 = 6  =>  0 pairs (X) / I5 = 6  =>  0 pairs (_)
H7,I7: 6.. / H7 = 6  =>  0 pairs (*) / I7 = 6  =>  0 pairs (X)
E2,E6: 6.. / E2 = 6  =>  0 pairs (X) / E6 = 6  => 17 pairs (_)
F2,F6: 6.. / F2 = 6  => 17 pairs (_) / F6 = 6  =>  0 pairs (X)
H5,H7: 6.. / H5 = 6  =>  0 pairs (X) / H7 = 6  =>  0 pairs (_)
I5,I7: 6.. / I5 = 6  =>  0 pairs (*) / I7 = 6  =>  0 pairs (X)
D1,D3: 7.. / D1 = 7  =>  0 pairs (X) / D3 = 7  => 16 pairs (_)
G4,I5: 7.. / G4 = 7  =>  0 pairs (*) / I5 = 7  =>  0 pairs (X)
A8,B9: 7.. / A8 = 7  =>  0 pairs (*) / B9 = 7  =>  0 pairs (X)
E7,F9: 7.. / E7 = 7  =>  0 pairs (X) / F9 = 7  =>  0 pairs (_)
I7,G8: 7.. / I7 = 7  =>  0 pairs (*) / G8 = 7  =>  0 pairs (X)
A3,D3: 7.. / A3 = 7  =>  0 pairs (X) / D3 = 7  => 16 pairs (_)
C4,G4: 7.. / C4 = 7  =>  0 pairs (X) / G4 = 7  =>  0 pairs (_)
E5,I5: 7.. / E5 = 7  =>  0 pairs (*) / I5 = 7  =>  0 pairs (X)
E7,I7: 7.. / E7 = 7  =>  0 pairs (X) / I7 = 7  =>  0 pairs (_)
A8,G8: 7.. / A8 = 7  =>  0 pairs (*) / G8 = 7  =>  0 pairs (X)
B9,F9: 7.. / B9 = 7  =>  0 pairs (X) / F9 = 7  =>  0 pairs (_)
B1,B9: 7.. / B1 = 7  =>  0 pairs (*) / B9 = 7  =>  0 pairs (X)
F6,F9: 7.. / F6 = 7  =>  0 pairs (X) / F9 = 7  =>  0 pairs (_)
G4,G8: 7.. / G4 = 7  =>  0 pairs (*) / G8 = 7  =>  0 pairs (X)
I5,I7: 7.. / I5 = 7  =>  0 pairs (X) / I7 = 7  =>  0 pairs (_)
G4,H5: 9.. / G4 = 9  =>  0 pairs (X) / H5 = 9  =>  0 pairs (_)
A8,B9: 9.. / A8 = 9  =>  0 pairs (X) / B9 = 9  =>  0 pairs (_)
H7,G8: 9.. / H7 = 9  =>  0 pairs (X) / G8 = 9  =>  0 pairs (_)
C4,G4: 9.. / C4 = 9  =>  0 pairs (*) / G4 = 9  =>  0 pairs (X)
E5,H5: 9.. / E5 = 9  =>  0 pairs (X) / H5 = 9  =>  0 pairs (_)
A8,G8: 9.. / A8 = 9  =>  0 pairs (X) / G8 = 9  =>  0 pairs (_)
B9,F9: 9.. / B9 = 9  =>  0 pairs (*) / F9 = 9  =>  0 pairs (X)
B1,B9: 9.. / B1 = 9  =>  0 pairs (X) / B9 = 9  =>  0 pairs (_)
G4,G8: 9.. / G4 = 9  =>  0 pairs (X) / G8 = 9  =>  0 pairs (_)
H5,H7: 9.. / H5 = 9  =>  0 pairs (*) / H7 = 9  =>  0 pairs (X)
* DURATION: 0:01:40.552715  START: 04:59:22.177675  END: 05:01:02.730390 2017-05-04
* CP COUNT: (44)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A8,B1,B9,C4,D3,D7,E5,F2,F9,G4,G8,H5,H7,I5,I7)
* 6...18234.43...871.18.4365916.432.853248.51...8.1..423851..43...32651.484.638.512
* PAIR B1: 7,9 BLK 1
C1: 7,9,5                                # reduction candidate for 7,9
C1: 5                                    # 19 pairs
C1: 7,9                                  # 17 pairs
* PAIR B1: 7,9 ROW 1
D1: 7,9,5                                # reduction candidate for 7,9
D1: 7,9                                  # 19 pairs
D1: 5                                    # 17 pairs
* PAIR F2: 6,9 BLK 2
E2: 6,9,2                                # reduction candidate for 6,9
E2: 6,9 => CTR
* 67..18234.43...8712187436591694327853248751965871..4238519243.7732651948496387512
E2: 2                                    # 17 pairs
* PAIR F2: 6,9 COL F
F6: 6,9,7                                # reduction candidate for 6,9
F6: 6,9 => SOLVED
* 675918234943526871218743659169432785324875196587169423851294367732651948496387512
F6: 7 => CTR
* 69..18234.43926871.18.4365916.432.853248.51...8.167423851.743.6.32651748476389512
* PAIR C4: 7,9 BLK 4
A6: 7,9,5                                # reduction candidate for 7,9
A6: 7,9                                  # 17 pairs
C6: 7,9,5                                # reduction candidate for 7,9
C6: 7,9                                  # 19 pairs
* PAIR C4: 7,9 COL C
C1: 7,9,5                                # reduction candidate for 7,9
C1: 5                                    # 19 pairs
C1: 7,9                                  # 17 pairs
* PAIR E5: 7,9 BLK 5
E6: 7,9,6                                # reduction candidate for 7,9
E6: 7,9 => CTR
* 679518234543269871218743659167432.853248.51...8.1.6423851924367732651948496387512
E6: 6                                    # 17 pairs
F6: 7,9,6                                # reduction candidate for 7,9
F6: 7,9                                  # 17 pairs
* PAIR E5: 7,9 COL E
E7: 7,9,2                                # reduction candidate for 7,9
E7: 2 => CTR
* 67..18234.43...8712187436591694327853248751965871..4238519243.7732651948496387512
E7: 7,9                                  # 17 pairs
* PAIR A8: 7,9 COL A
A6: 7,9,5                                # reduction candidate for 7,9
A6: 5                                    # 19 pairs
A6: 7,9                                  # 17 pairs
* PAIR D7: 2,9 BLK 8
E7: 2,9,7                                # reduction candidate for 2,9
E7: 2,9 => SOLVED
* 675918234943526871218743659169432785324875196587169423851294367732651948496387512
E7: 7 => CTR
* 697518234543926871218743659169432.853248.51...8.16.423851274396932651748476389512
* PAIR D7: 2,9 COL D
D2: 2,9,5                                # reduction candidate for 2,9
D2: 5                                    # 19 pairs
D2: 2,9                                  # 17 pairs
* PAIR F9: 7,9 BLK 8
E7: 7,9,2                                # reduction candidate for 7,9
E7: 2 => CTR
* 67..18234.43...8712187436591694327853248751965871..4238519243.7732651948496387512
E7: 7,9                                  # 17 pairs
* PAIR F9: 7,9 COL F
F6: 7,9,6                                # reduction candidate for 7,9
F6: 6 => CTR
* 679518234543269871218743659167432.853248.51...8.1.6423851924367732651948496387512
F6: 7,9                                  # 17 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-068-base-pr-000.dot
* REASONING
* DIS # E2: 6,9 => CTR => E2: 2
* PRF # F6: 6,9 => SOL
* DIS # F6: 7 => CTR => F6: 6,9
* DIS # E6: 7,9 => CTR => E6: 6
* DIS # E7: 2 => CTR => E7: 7,9
* PRF # E7: 2,9 => SOL
* DIS # E7: 7 => CTR => E7: 2,9
* DIS # E7: 2 => CTR => E7: 7,9
* DIS # F6: 6 => CTR => F6: 7,9
* CNT   9 HDP CHAINS /  27 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,A8,B1,B9,C4,D3,D7,E5,F2,F9,G4,G8,H5,H7,I5,I7)
* 6...18234.43...871.18.4365916.432.853248.51...8.1..423851..43...32651.484.638.512
* PAIR B1: 7,9 BLK 1
C1: 7,9,5                                # reduction candidate for 7,9
C1: 5                                    # 19 pairs
C1: 7,9                                  # 17 pairs
* PAIR B1: 7,9 ROW 1
D1: 7,9,5                                # reduction candidate for 7,9
D1: 7,9                                  # 19 pairs
D1: 5                                    # 17 pairs
* PAIR F2: 6,9 BLK 2
E2: 6,9,2                                # reduction candidate for 6,9
E2: 6,9 => CTR
* 67..18234.43...8712187436591694327853248751965871..4238519243.7732651948496387512
* PAIR C4: 7,9 BLK 4
A6: 7,9,5                                # reduction candidate for 7,9
A6: 7,9                                  # 16 pairs
C6: 7,9,5                                # reduction candidate for 7,9
C6: 7,9 => SOLVED
* 675918234943526871218743659169432785324875196587169423851294367732651948496387512
* DURATION: 0:00:11.368809  START: 05:01:38.401395  END: 05:01:49.770204 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-068-base-pr-001.dot
* REASONING
* DIS # E2: 6,9 => CTR => E2: 2
* PRF E2: 2 # C6: 7,9 => SOL
* STA E2: 2 + C6: 7,9
* CNT   2 HDP CHAINS /   7 HYP OPENED

Header Info

Top 500 Minimum 17 068

solution: 675918234943526871218743659169432785324875196587169423851294367732651948496387512
info: 1446     FNBHWX   S8.f     3146

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

Solution

position: 675918234943526871218743659169432785324875196587169423851294367732651948496387512 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 # C1: 7,9 => UNS
* INC # C1: 5 => UNS
* INC # D1: 7,9 => UNS
* INC # D1: 5 => UNS
* DIS # E2: 6,9 => CTR => E2: 2
* INC # E2: 2 => UNS
* PRF # F6: 6,9 => SOL
* DIS # F6: 7 => CTR => F6: 6,9
* INC # A6: 7,9 => UNS
* INC # C6: 7,9 => UNS
* INC # C1: 7,9 => UNS
* INC # C1: 5 => UNS
* DIS # E6: 7,9 => CTR => E6: 6
* INC # E6: 6 => UNS
* INC # F6: 7,9 => UNS
* INC # E7: 7,9 => UNS
* DIS # E7: 2 => CTR => E7: 7,9
* INC # A6: 7,9 => UNS
* INC # A6: 5 => UNS
* PRF # E7: 2,9 => SOL
* DIS # E7: 7 => CTR => E7: 2,9
* INC # D2: 2,9 => UNS
* INC # D2: 5 => UNS
* INC # E7: 7,9 => UNS
* DIS # E7: 2 => CTR => E7: 7,9
* INC # F6: 7,9 => UNS
* DIS # F6: 6 => CTR => F6: 7,9
* CNT  27 HDP CHAINS /  27 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # C1: 7,9 => UNS
* INC # C1: 5 => UNS
* INC # D1: 7,9 => UNS
* INC # D1: 5 => UNS
* DIS # E2: 6,9 => CTR => E2: 2
* INC E2: 2 # A6: 7,9 => UNS
* PRF E2: 2 # C6: 7,9 => SOL
* STA E2: 2 + C6: 7,9
* CNT   7 HDP CHAINS /   7 HYP OPENED