Analysis of xx-top500-072-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....56.......7..9.........1......37..6....5..1..4.....4..1...8..5....7.....2..... initial

Autosolve

position: .1..56.37....71.9.....24..1...51.376.6.7..514175463.2.4..1...8..516..74....24.1.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A3: 7 => CTR => A3: 5,6
* DIS # B2: 3,8 => CTR => B2: 2,4
* DIS # C3: 6,8 => CTR => C3: 3,7,9
* DIS # A3: 7 => CTR => A3: 5,6
* DIS # C9: 6,7 => CTR => C9: 3,8,9
* DIS # A3: 5 => CTR => A3: 6,7
* DIS # C7: 3,9 => CTR => C7: 2,6,7
* DIS # I7: 3,9 => CTR => I7: 2,5
* CNT   8 HDP CHAINS /  39 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 # A3: 7 => CTR => A3: 5,6
* PRF A3: 5,6 # E8: 8,9 => SOL
* STA A3: 5,6 + E8: 8,9
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

....56.......7..9.........1......37..6....5..1..4.....4..1...8..5....7.....2..... initial
.1..56.37....71.9.....24..1...51.376.6.7..514175463.2.4..1...8..516..74....24.1.. autosolve
912856437548371692637924851824519376369782514175463928496137285251698743783245169 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (14)
A2: 5,6
D1: 8,9
D2: 3,8
G3: 6,8
H3: 5,6
E5: 8,9
G6: 8,9
I6: 8,9
A9: 6,7
E7: 3,9
F7: 5,7
F8: 8,9
F9: 5,7
H9: 5,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
F4,F5: 2.. / F4 = 2  => 18 pairs (_) / F5 = 2  => 15 pairs (_)
A8,I8: 2.. / A8 = 2  => 25 pairs (_) / I8 = 2  => 20 pairs (_)
D2,D3: 3.. / D2 = 3  => 14 pairs (_) / D3 = 3  => 14 pairs (_)
A5,C5: 3.. / A5 = 3  => 15 pairs (_) / C5 = 3  => 23 pairs (_)
E7,E8: 3.. / E7 = 3  => 17 pairs (_) / E8 = 3  => 17 pairs (_)
A5,A8: 3.. / A5 = 3  => 15 pairs (_) / A8 = 3  => 23 pairs (_)
G1,G2: 4.. / G1 = 4  => 14 pairs (_) / G2 = 4  => 16 pairs (_)
B4,C4: 4.. / B4 = 4  => 14 pairs (_) / C4 = 4  => 14 pairs (_)
C1,G1: 4.. / C1 = 4  => 16 pairs (_) / G1 = 4  => 14 pairs (_)
B2,B4: 4.. / B2 = 4  => 14 pairs (_) / B4 = 4  => 14 pairs (_)
A2,A3: 5.. / A2 = 5  => 16 pairs (_) / A3 = 5  =>  0 pairs (X)
I2,H3: 5.. / I2 = 5  =>  0 pairs (X) / H3 = 5  => 16 pairs (_)
F7,F9: 5.. / F7 = 5  =>  0 pairs (X) / F9 = 5  => 16 pairs (_)
A2,I2: 5.. / A2 = 5  => 16 pairs (_) / I2 = 5  =>  0 pairs (X)
A3,H3: 5.. / A3 = 5  =>  0 pairs (X) / H3 = 5  => 16 pairs (_)
F7,I7: 5.. / F7 = 5  =>  0 pairs (X) / I7 = 5  => 16 pairs (_)
H3,H9: 5.. / H3 = 5  => 16 pairs (_) / H9 = 5  =>  0 pairs (X)
G7,H9: 6.. / G7 = 6  =>  0 pairs (X) / H9 = 6  => 16 pairs (_)
C7,G7: 6.. / C7 = 6  => 16 pairs (_) / G7 = 6  =>  0 pairs (X)
H3,H9: 6.. / H3 = 6  =>  0 pairs (X) / H9 = 6  => 16 pairs (_)
A3,C3: 7.. / A3 = 7  =>  0 pairs (X) / C3 = 7  => 16 pairs (_)
F7,F9: 7.. / F7 = 7  => 16 pairs (_) / F9 = 7  =>  0 pairs (X)
C7,F7: 7.. / C7 = 7  =>  0 pairs (X) / F7 = 7  => 16 pairs (_)
A3,A9: 7.. / A3 = 7  =>  0 pairs (X) / A9 = 7  => 16 pairs (_)
G6,I6: 8.. / G6 = 8  =>  0 pairs (X) / I6 = 8  => 14 pairs (_)
B9,C9: 8.. / B9 = 8  => 18 pairs (_) / C9 = 8  => 17 pairs (_)
E8,F8: 8.. / E8 = 8  => 16 pairs (_) / F8 = 8  => 15 pairs (_)
E5,E8: 8.. / E5 = 8  => 15 pairs (_) / E8 = 8  => 16 pairs (_)
I2,I6: 8.. / I2 = 8  =>  0 pairs (X) / I6 = 8  => 14 pairs (_)
D1,D3: 9.. / D1 = 9  => 15 pairs (_) / D3 = 9  => 15 pairs (_)
G6,I6: 9.. / G6 = 9  => 14 pairs (_) / I6 = 9  =>  0 pairs (X)
G6,G7: 9.. / G6 = 9  => 14 pairs (_) / G7 = 9  =>  0 pairs (X)
* DURATION: 0:01:02.372948  START: 05:09:40.000733  END: 05:10:42.373681 2017-05-04
* CP COUNT: (32)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A9,D1,D2,E5,E7,F7,F8,F9,G3,G6,H3,H9,I6)
* .1..56.37....71.9.....24..1...51.376.6.7..514175463.2.4..1...8..516..74....24.1..
* PAIR A2: 5,6 BLK 1
A3: 5,6,7                                # reduction candidate for 5,6
A3: 7 => CTR
* .1..56.375...71.9.7...24.51...51.376.6.7..514175463.2.4..1...8..516..74.6..24.1..
A3: 5,6                                  # 16 pairs
* PAIR D1: 8,9 BLK 2
D3: 8,9,3                                # reduction candidate for 8,9
D3: 8,9                                  # 14 pairs
D3: 3                                    # 14 pairs
* PAIR D1: 8,9 ROW 1
A1: 8,9,2                                # reduction candidate for 8,9
A1: 8,9                                  # 17 pairs
C1: 8,9,2,4                              # reduction candidate for 8,9
C1: 8,9                                  # 20 pairs
* PAIR D2: 3,8 BLK 2
D3: 3,8,9                                # reduction candidate for 3,8
D3: 9                                    # 15 pairs
D3: 3,8                                  # 15 pairs
* PAIR D2: 3,8 ROW 2
B2: 3,8,2,4                              # reduction candidate for 3,8
B2: 3,8 => CTR
* .1..56.376...71.955.7.24861.4.51.376.6.7..51417546392842.1...8..516..742...24.1..
B2: 2,4                                  # 15 pairs
C2: 3,8,2,4,6                            # reduction candidate for 3,8
C2: 3,8                                  # 19 pairs
* PAIR G3: 6,8 BLK 3
G2: 6,8,2,4                              # reduction candidate for 6,8
G2: 6,8                                  # 16 pairs
G2: 2,4                                  # 16 pairs
* PAIR G3: 6,8 ROW 3
C3: 6,8,3,7,9                            # reduction candidate for 6,8
C3: 6,8 => CTR
* .1..56.37....71.9.7...24.51...51.376.6.7..514175463.2.4..1...8..516..74.6..24.1..
C3: 3,7,9                                # 14 pairs
* PAIR H3: 5,6 ROW 3
A3: 5,6,7                                # reduction candidate for 5,6
A3: 7 => CTR
* .1..56.375...71.9.7...24.51...51.376.6.7..514175463.2.4..1...8..516..74.6..24.1..
A3: 5,6                                  # 16 pairs
* PAIR E5: 8,9 BLK 5
F4: 8,9,2                                # reduction candidate for 8,9
F4: 8,9                                  # 15 pairs
F5: 8,9,2                                # reduction candidate for 8,9
F5: 8,9                                  # 18 pairs
* PAIR E5: 8,9 ROW 5
A5: 8,9,2,3                              # reduction candidate for 8,9
A5: 8,9                                  # 25 pairs
C5: 8,9,2,3                              # reduction candidate for 8,9
C5: 8,9                                  # 17 pairs
* PAIR E5: 8,9 COL E
E8: 8,9,3                                # reduction candidate for 8,9
E8: 8,9                                  # 17 pairs
E8: 3                                    # 17 pairs
* PAIR A9: 6,7 BLK 7
C7: 6,7,2,3,9                            # reduction candidate for 6,7
C7: 6,7                                  # 15 pairs
C9: 6,7,3,8,9                            # reduction candidate for 6,7
C9: 6,7 => CTR
* .1..56.37....71.9.....24..1...51.376.6.7..514175463.2.4..1...8..516..74..8.24.1..
C9: 3,8,9                                # 15 pairs
* PAIR A9: 6,7 COL A
A3: 6,7,5                                # reduction candidate for 6,7
A3: 5 => CTR
* .1..56.37....71.9.5.7.24.61...51.376.6.7..514175463.2.4..1.7685.516..74....24.1..
A3: 6,7                                  # 16 pairs
* PAIR E7: 3,9 BLK 8
E8: 3,9,8                                # reduction candidate for 3,9
E8: 8                                    # 16 pairs
E8: 3,9                                  # 15 pairs
* PAIR E7: 3,9 ROW 7
B7: 3,9,2                                # reduction candidate for 3,9
B7: 3,9                                  # 25 pairs
C7: 3,9,2,6,7                            # reduction candidate for 3,9
C7: 3,9 => CTR
* .1..56.37....71.9.....24..1...51.376.6.7..514175463.2.4..1.7685.516..74....24.1..
C7: 2,6,7                                # 14 pairs
I7: 3,9,2,5                              # reduction candidate for 3,9
I7: 3,9 => CTR
* .1..56.37....71.9.7...24.51...51.376.6.7..514175463.2.4.71.568..516..74....2471..
I7: 2,5                                  # 15 pairs
* PAIR F8: 8,9 BLK 8
E8: 8,9,3                                # reduction candidate for 8,9
E8: 8,9                                  # 17 pairs
E8: 3                                    # 17 pairs
* PAIR F8: 8,9 COL F
F4: 8,9,2                                # reduction candidate for 8,9
F4: 8,9                                  # 15 pairs
F5: 8,9,2                                # reduction candidate for 8,9
F5: 8,9                                  # 18 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-072-base-pr-000.dot
* REASONING
* DIS # A3: 7 => CTR => A3: 5,6
* DIS # B2: 3,8 => CTR => B2: 2,4
* DIS # C3: 6,8 => CTR => C3: 3,7,9
* DIS # A3: 7 => CTR => A3: 5,6
* DIS # C9: 6,7 => CTR => C9: 3,8,9
* DIS # A3: 5 => CTR => A3: 6,7
* DIS # C7: 3,9 => CTR => C7: 2,6,7
* DIS # I7: 3,9 => CTR => I7: 2,5
* CNT   8 HDP CHAINS /  39 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A9,D1,D2,E5,E7,F7,F8,F9,G3,G6,H3,H9,I6)
* .1..56.37....71.9.....24..1...51.376.6.7..514175463.2.4..1...8..516..74....24.1..
* PAIR A2: 5,6 BLK 1
A3: 5,6,7                                # reduction candidate for 5,6
A3: 7 => CTR
* .1..56.375...71.9.7...24.51...51.376.6.7..514175463.2.4..1...8..516..74.6..24.1..
* PAIR E5: 8,9 COL E
E8: 8,9,3                                # reduction candidate for 8,9
E8: 8,9 => SOLVED
* 912856437548371692637924851824519376369782514175463928496137285251698743783245169
* DURATION: 0:00:04.998887  START: 05:11:21.688774  END: 05:11:26.687661 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-072-base-pr-001.dot
* REASONING
* DIS # A3: 7 => CTR => A3: 5,6
* PRF A3: 5,6 # E8: 8,9 => SOL
* STA A3: 5,6 + E8: 8,9
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 072

solution: 912856437548371692637924851824519376369782514175463928496137285251698743783245169
info: 1467     FNBTHXY  S8.f     5042

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

Solution

position: 912856437548371692637924851824519376369782514175463928496137285251698743783245169 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 # A3: 5,6 => UNS
* DIS # A3: 7 => CTR => A3: 5,6
* INC # D3: 8,9 => UNS
* INC # D3: 3 => UNS
* INC # A1: 8,9 => UNS
* INC # C1: 8,9 => UNS
* INC # D3: 3,8 => UNS
* INC # D3: 9 => UNS
* DIS # B2: 3,8 => CTR => B2: 2,4
* INC # B2: 2,4 => UNS
* INC # C2: 3,8 => UNS
* INC # G2: 6,8 => UNS
* INC # G2: 2,4 => UNS
* DIS # C3: 6,8 => CTR => C3: 3,7,9
* INC # C3: 3,7,9 => UNS
* INC # A3: 5,6 => UNS
* DIS # A3: 7 => CTR => A3: 5,6
* INC # F4: 8,9 => UNS
* INC # F5: 8,9 => UNS
* INC # A5: 8,9 => UNS
* INC # C5: 8,9 => UNS
* INC # E8: 8,9 => UNS
* INC # E8: 3 => UNS
* INC # C7: 6,7 => UNS
* DIS # C9: 6,7 => CTR => C9: 3,8,9
* INC # C9: 3,8,9 => UNS
* INC # A3: 6,7 => UNS
* DIS # A3: 5 => CTR => A3: 6,7
* INC # E8: 3,9 => UNS
* INC # E8: 8 => UNS
* INC # B7: 3,9 => UNS
* DIS # C7: 3,9 => CTR => C7: 2,6,7
* INC # C7: 2,6,7 => UNS
* DIS # I7: 3,9 => CTR => I7: 2,5
* INC # I7: 2,5 => UNS
* INC # E8: 8,9 => UNS
* INC # E8: 3 => UNS
* INC # F4: 8,9 => UNS
* INC # F5: 8,9 => UNS
* CNT  39 HDP CHAINS /  39 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A3: 5,6 => UNS
* DIS # A3: 7 => CTR => A3: 5,6
* PRF A3: 5,6 # E8: 8,9 => SOL
* STA A3: 5,6 + E8: 8,9
* CNT   3 HDP CHAINS /   3 HYP OPENED