Analysis of xx-top500-085-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 14....7........4.....8.....8.2..3.......4.6.........1..6.57.......1....2.......8. initial

Autosolve

position: 14.3257.828.7.143..3.8.42.18.26139...1394862..9.2578133685721.....18.3.2.2143.58. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C2: 6,9 => CTR => C2: 5
* DIS # C3: 6,9 => CTR => C3: 5,7
* DIS # C2: 6,9 => CTR => C2: 5
* DIS # C3: 6,9 => CTR => C3: 5,7
* DIS # H3: 6,9 => CTR => H3: 5
* DIS # H3: 6,9 => CTR => H3: 5
* PRF # I4: 5,7 => SOL
* DIS # A3: 5,7 => CTR => A3: 6,9
* DIS # A8: 5,7 => CTR => A8: 4,9
* PRF # I4: 5,7 => SOL
* DIS # A8: 5,7 => CTR => A8: 4,9
* DIS # C8: 5,7 => CTR => C8: 4,9
* PRF # A8: 7,9 => SOL
* DIS # C8: 7,9 => CTR => C8: 4,5
* DIS # A3: 7,9 => CTR => A3: 5,6
* CNT  15 HDP CHAINS /  36 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 # C2: 6,9 => CTR => C2: 5
* DIS C2: 5 # C3: 6,9 => CTR => C3: 7
* PRF C2: 5 + C3: 7 # I4: 5,7 => SOL
* STA C2: 5 + C3: 7 + I4: 5,7
* CNT   3 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

14....7........4.....8.....8.2..3.......4.6.........1..6.57.......1....2.......8. initial
14.3257.828.7.143..3.8.42.18.26139...1394862..9.2578133685721.....18.3.2.2143.58. autosolve
149325768285761439637894251872613945513948627496257813368572194954186372721439586 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (17)
C1: 6,9
E2: 6,9
E3: 6,9
H1: 6,9
B4: 5,7
A5: 5,7
A6: 4,6
C6: 4,6
I5: 5,7
B8: 5,7
A9: 7,9
F8: 6,9
F9: 6,9
H7: 4,9
I7: 4,9
H8: 6,7
I9: 6,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A6,C6: 4.. / A6 = 4  =>  0 pairs (*) / C6 = 4  =>  0 pairs (X)
H4,I4: 4.. / H4 = 4  =>  0 pairs (*) / I4 = 4  =>  0 pairs (X)
A8,C8: 4.. / A8 = 4  => 15 pairs (_) / C8 = 4  =>  0 pairs (*)
H7,I7: 4.. / H7 = 4  => 17 pairs (_) / I7 = 4  =>  0 pairs (*)
A6,A8: 4.. / A6 = 4  =>  0 pairs (*) / A8 = 4  =>  0 pairs (X)
C6,C8: 4.. / C6 = 4  => 15 pairs (_) / C8 = 4  =>  0 pairs (*)
H4,H7: 4.. / H4 = 4  =>  0 pairs (*) / H7 = 4  =>  0 pairs (X)
I4,I7: 4.. / I4 = 4  => 17 pairs (_) / I7 = 4  =>  0 pairs (*)
I2,H3: 5.. / I2 = 5  =>  0 pairs (X) / H3 = 5  => 19 pairs (_)
B4,A5: 5.. / B4 = 5  =>  0 pairs (X) / A5 = 5  =>  0 pairs (_)
C2,I2: 5.. / C2 = 5  => 19 pairs (_) / I2 = 5  =>  0 pairs (X)
A5,I5: 5.. / A5 = 5  =>  0 pairs (*) / I5 = 5  =>  0 pairs (X)
B4,B8: 5.. / B4 = 5  =>  0 pairs (X) / B8 = 5  =>  0 pairs (_)
H3,H4: 5.. / H3 = 5  => 19 pairs (_) / H4 = 5  =>  0 pairs (X)
E2,E3: 6.. / E2 = 6  =>  0 pairs (*) / E3 = 6  =>  0 pairs (X)
A6,C6: 6.. / A6 = 6  => 15 pairs (_) / C6 = 6  =>  0 pairs (*)
F8,F9: 6.. / F8 = 6  =>  0 pairs (*) / F9 = 6  =>  0 pairs (X)
H8,I9: 6.. / H8 = 6  =>  0 pairs (X) / I9 = 6  =>  0 pairs (_)
C1,H1: 6.. / C1 = 6  => 15 pairs (_) / H1 = 6  =>  0 pairs (*)
F8,H8: 6.. / F8 = 6  =>  0 pairs (*) / H8 = 6  =>  0 pairs (X)
F9,I9: 6.. / F9 = 6  =>  0 pairs (X) / I9 = 6  =>  0 pairs (_)
A3,A6: 6.. / A3 = 6  =>  0 pairs (*) / A6 = 6  =>  0 pairs (X)
I2,I9: 6.. / I2 = 6  =>  0 pairs (X) / I9 = 6  =>  0 pairs (_)
A3,C3: 7.. / A3 = 7  =>  0 pairs (X) / C3 = 7  => 17 pairs (_)
B4,A5: 7.. / B4 = 7  =>  0 pairs (*) / A5 = 7  =>  0 pairs (X)
H8,I9: 7.. / H8 = 7  =>  0 pairs (*) / I9 = 7  =>  0 pairs (X)
A5,I5: 7.. / A5 = 7  =>  0 pairs (X) / I5 = 7  =>  0 pairs (_)
A9,I9: 7.. / A9 = 7  =>  0 pairs (*) / I9 = 7  =>  0 pairs (X)
B4,B8: 7.. / B4 = 7  =>  0 pairs (*) / B8 = 7  =>  0 pairs (X)
C3,C8: 7.. / C3 = 7  => 17 pairs (_) / C8 = 7  =>  0 pairs (X)
H4,H8: 7.. / H4 = 7  =>  0 pairs (X) / H8 = 7  =>  0 pairs (_)
E2,E3: 9.. / E2 = 9  => 15 pairs (_) / E3 = 9  =>  0 pairs (*)
F8,F9: 9.. / F8 = 9  =>  0 pairs (X) / F9 = 9  =>  0 pairs (_)
H7,I7: 9.. / H7 = 9  =>  0 pairs (*) / I7 = 9  =>  0 pairs (X)
C1,H1: 9.. / C1 = 9  =>  0 pairs (*) / H1 = 9  =>  0 pairs (X)
A9,F9: 9.. / A9 = 9  =>  0 pairs (X) / F9 = 9  =>  0 pairs (_)
I2,I7: 9.. / I2 = 9  =>  0 pairs (*) / I7 = 9  =>  0 pairs (X)
* DURATION: 0:01:06.799833  START: 05:41:15.470124  END: 05:42:22.269957 2017-05-04
* CP COUNT: (37)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A6,A9,B4,B8,C1,C6,E2,E3,F8,F9,H1,H7,H8,I5,I7,I9)
* 14.3257.828.7.143..3.8.42.18.26139...1394862..9.2578133685721.....18.3.2.2143.58.
* PAIR C1: 6,9 BLK 1
C2: 6,9,5                                # reduction candidate for 6,9
C2: 6,9 => CTR
* 14.3257.828.7.1435.3.8.42.18.2613954513948627.9.257813368572149.5.18.372721439586
C2: 5                                    # 19 pairs
A3: 6,9,5,7                              # reduction candidate for 6,9
A3: 6,9                                  # 21 pairs
C3: 6,9,5,7                              # reduction candidate for 6,9
C3: 6,9 => CTR
* 14.3257.828.7.143.73.8.4251872613945513948627694257813368572194457189362.2143.58.
C3: 5,7                                  # 18 pairs
* PAIR E2: 6,9 ROW 2
C2: 6,9,5                                # reduction candidate for 6,9
C2: 6,9 => CTR
* 14.3257.828.7.1435.3.8.42.18.2613954513948627.9.257813368572149.5.18.372721439586
C2: 5                                    # 19 pairs
I2: 6,9,5                                # reduction candidate for 6,9
I2: 6,9                                  # 19 pairs
* PAIR E3: 6,9 ROW 3
A3: 6,9,5,7                              # reduction candidate for 6,9
A3: 6,9                                  # 21 pairs
C3: 6,9,5,7                              # reduction candidate for 6,9
C3: 6,9 => CTR
* 14.3257.828.7.143.73.8.4251872613945513948627694257813368572194457189362.2143.58.
C3: 5,7                                  # 18 pairs
H3: 6,9,5                                # reduction candidate for 6,9
H3: 6,9 => CTR
* 14.3257.828.7.1435.3.8.42.18.2613954513948627.9.257813368572149.5.18.372721439586
H3: 5                                    # 19 pairs
* PAIR H1: 6,9 BLK 3
I2: 6,9,5                                # reduction candidate for 6,9
I2: 6,9                                  # 19 pairs
H3: 6,9,5                                # reduction candidate for 6,9
H3: 6,9 => CTR
* 14.3257.828.7.1435.3.8.42.18.2613954513948627.9.257813368572149.5.18.372721439586
H3: 5                                    # 19 pairs
* PAIR B4: 5,7 ROW 4
H4: 5,7,4                                # reduction candidate for 5,7
H4: 5,7                                  # 17 pairs
I4: 5,7,4                                # reduction candidate for 5,7
I4: 5,7 => SOLVED
* 149325768285761439637894251872613945513948627496257813368572194954186372721439586
I4: 4                                    # 17 pairs
* PAIR A5: 5,7 COL A
A3: 5,7,6,9                              # reduction candidate for 5,7
A3: 5,7 => CTR
* 14.3257.828.7.1436.3.8642518.2613974.1394862.6942578133685721..4..18.3.2921436587
A3: 6,9                                  # 21 pairs
A8: 5,7,4,9                              # reduction candidate for 5,7
A8: 5,7 => CTR
* 14.3257.828.7.143..3.8.42.18.26139...1394862.4962578133685721....4189362921436587
A8: 4,9                                  # 18 pairs
* PAIR I5: 5,7 BLK 6
H4: 5,7,4                                # reduction candidate for 5,7
H4: 5,7                                  # 17 pairs
I4: 5,7,4                                # reduction candidate for 5,7
I4: 5,7 => SOLVED
* 149325768285761439637894251872613945513948627496257813368572194954186372721439586
I4: 4                                    # 17 pairs
* PAIR B8: 5,7 BLK 7
A8: 5,7,4,9                              # reduction candidate for 5,7
A8: 5,7 => CTR
* 14.3257.828.7.143..3.8.42.18.26139...1394862.4962578133685721....4189362921436587
A8: 4,9                                  # 18 pairs
C8: 5,7,4,9                              # reduction candidate for 5,7
C8: 5,7 => CTR
* 14632579828.7.1436.3.8642518.2613974.1394862..942578133685721..4..189362921436587
C8: 4,9                                  # 21 pairs
* PAIR A9: 7,9 BLK 7
A8: 7,9,4,5                              # reduction candidate for 7,9
A8: 7,9 => SOLVED
* 149325768285761439637894251872613945513948627496257813368572194954186372721439586
A8: 4,5                                  # 18 pairs
C8: 7,9,4,5                              # reduction candidate for 7,9
C8: 7,9 => CTR
* 14.3257.828.7.143.9378642518726139..5139486276942578133685721..45.18.372721439586
C8: 4,5                                  # 19 pairs
* PAIR A9: 7,9 COL A
A3: 7,9,5,6                              # reduction candidate for 7,9
A3: 7,9 => CTR
* 14.3257.828.7.143.9378642518.26139..5139486276942578133685721..45.18.372721439586
A3: 5,6                                  # 19 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-085-base-pr-000.dot
* REASONING
* DIS # C2: 6,9 => CTR => C2: 5
* DIS # C3: 6,9 => CTR => C3: 5,7
* DIS # C2: 6,9 => CTR => C2: 5
* DIS # C3: 6,9 => CTR => C3: 5,7
* DIS # H3: 6,9 => CTR => H3: 5
* DIS # H3: 6,9 => CTR => H3: 5
* PRF # I4: 5,7 => SOL
* DIS # A3: 5,7 => CTR => A3: 6,9
* DIS # A8: 5,7 => CTR => A8: 4,9
* PRF # I4: 5,7 => SOL
* DIS # A8: 5,7 => CTR => A8: 4,9
* DIS # C8: 5,7 => CTR => C8: 4,9
* PRF # A8: 7,9 => SOL
* DIS # C8: 7,9 => CTR => C8: 4,5
* DIS # A3: 7,9 => CTR => A3: 5,6
* CNT  15 HDP CHAINS /  36 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A5,A6,A9,B4,B8,C1,C6,E2,E3,F8,F9,H1,H7,H8,I5,I7,I9)
* 14.3257.828.7.143..3.8.42.18.26139...1394862..9.2578133685721.....18.3.2.2143.58.
* PAIR C1: 6,9 BLK 1
C2: 6,9,5                                # reduction candidate for 6,9
C2: 6,9 => CTR
* 14.3257.828.7.1435.3.8.42.18.2613954513948627.9.257813368572149.5.18.372721439586
A3: 6,9,7                                # reduction candidate for 6,9
A3: 6,9                                  # 21 pairs
C3: 6,9,7                                # reduction candidate for 6,9
C3: 6,9 => CTR
* 14.3257.82857.143.73.8.4251872613945513948627694257813368572194457189362.2143.58.
* RESTART
* PAIR B4: 5,7 ROW 4
I4: 5,7,4                                # reduction candidate for 5,7
I4: 5,7 => SOLVED
* 149325768285761439637894251872613945513948627496257813368572194954186372721439586
* DURATION: 0:00:05.508183  START: 05:42:59.703374  END: 05:43:05.211557 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-085-base-pr-001.dot
* REASONING
* DIS # C2: 6,9 => CTR => C2: 5
* DIS C2: 5 # C3: 6,9 => CTR => C3: 7
* PRF C2: 5 + C3: 7 # I4: 5,7 => SOL
* STA C2: 5 + C3: 7 + I4: 5,7
* CNT   3 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 085

solution: 149325768285761439637894251872613945513948627496257813368572194954186372721439586
info: 1558     FNBWXY   S8.f     26423

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

Solution

position: 149325768285761439637894251872613945513948627496257813368572194954186372721439586 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 # C2: 6,9 => CTR => C2: 5
* INC # C2: 5 => UNS
* INC # A3: 6,9 => UNS
* DIS # C3: 6,9 => CTR => C3: 5,7
* INC # C3: 5,7 => UNS
* DIS # C2: 6,9 => CTR => C2: 5
* INC # C2: 5 => UNS
* INC # I2: 6,9 => UNS
* INC # A3: 6,9 => UNS
* DIS # C3: 6,9 => CTR => C3: 5,7
* INC # C3: 5,7 => UNS
* DIS # H3: 6,9 => CTR => H3: 5
* INC # H3: 5 => UNS
* INC # I2: 6,9 => UNS
* DIS # H3: 6,9 => CTR => H3: 5
* INC # H3: 5 => UNS
* INC # H4: 5,7 => UNS
* PRF # I4: 5,7 => SOL
* INC # I4: 4 => UNS
* DIS # A3: 5,7 => CTR => A3: 6,9
* INC # A3: 6,9 => UNS
* DIS # A8: 5,7 => CTR => A8: 4,9
* INC # A8: 4,9 => UNS
* INC # H4: 5,7 => UNS
* PRF # I4: 5,7 => SOL
* INC # I4: 4 => UNS
* DIS # A8: 5,7 => CTR => A8: 4,9
* INC # A8: 4,9 => UNS
* DIS # C8: 5,7 => CTR => C8: 4,9
* INC # C8: 4,9 => UNS
* PRF # A8: 7,9 => SOL
* INC # A8: 4,5 => UNS
* DIS # C8: 7,9 => CTR => C8: 4,5
* INC # C8: 4,5 => UNS
* DIS # A3: 7,9 => CTR => A3: 5,6
* INC # A3: 5,6 => UNS
* CNT  36 HDP CHAINS /  36 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # C2: 6,9 => CTR => C2: 5
* INC C2: 5 # A3: 6,9 => UNS
* DIS C2: 5 # C3: 6,9 => CTR => C3: 7
* PRF C2: 5 + C3: 7 # I4: 5,7 => SOL
* STA C2: 5 + C3: 7 + I4: 5,7
* CNT   4 HDP CHAINS /   4 HYP OPENED