Analysis of xx-top500-423-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .......31.28..................2.84..73.....6....5.....16..7.......4..2..3........ initial

Autosolve

position: .76....31.28.......13....286912384..735...862284567...16..7....85.4..2..34....... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # E2: 5,9 => CTR => E2: 1
* PRF # E2: 1 => SOL
* PRF # G2: 5,9 => SOL
* DIS # H2: 5,9 => CTR => H2: 4,7
* DIS # I2: 5,9 => CTR => I2: 4,6,7
* DIS # D9: 8,9 => CTR => D9: 1,6
* PRF # G2: 5,9 => SOL
* DIS # H2: 5,9 => CTR => H2: 4,7
* DIS # I2: 5,9 => CTR => I2: 4,6,7
* DIS # G3: 5,9 => CTR => G3: 6,7
* DIS # G7: 5,9 => CTR => G7: 3
* DIS # G9: 5,9 => CTR => G9: 1,6,7
* DIS # E5: 1,9 => CTR => E5: 4
* DIS # D2: 1,9 => CTR => D2: 3,6,7
* DIS # D9: 1,9 => CTR => D9: 6,8
* PRF # H2: 5,7 => SOL
* DIS # G6: 3 => CTR => G6: 1,9
* DIS # H9: 1,9 => CTR => H9: 5,7,8
* DIS # G6: 3,9 => CTR => G6: 1
* DIS # C9: 7 => CTR => C9: 2,9
* DIS # C9: 2 => CTR => C9: 7,9
* DIS # H8: 7,9 => CTR => H8: 1
* PRF # H8: 1 => SOL
* DIS # D9: 1,9 => CTR => D9: 6,8
* DIS # H8: 7 => CTR => H8: 1,9
* DIS # E5: 1,9 => CTR => E5: 4
* PRF # F2: 3,6 => SOL
* DIS # F2: 1,9 => CTR => F2: 3,6
* CNT  28 HDP CHAINS /  66 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: 5,9 => CTR => E2: 1
* PRF E2: 1 => SOL
* STA E2: 1
* CNT   2 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

.......31.28..................2.84..73.....6....5.....16..7.......4..2..3........ initial
.76....31.28.......13....286912384..735...862284567...16..7....85.4..2..34....... autosolve
476982531528316974913754628691238457735149862284567193162875349857493216349621785 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (15)
A2: 5,9
D1: 8,9
E1: 2,8
G1: 5,9
D5: 1,9
H4: 5,7
I4: 5,7
H6: 1,9
I6: 3,9
C7: 2,9
C8: 7,9
E8: 1,9
F8: 3,6
E9: 2,8
I8: 3,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
G6,H6: 1.. / G6 = 1  => 14 pairs (_) / H6 = 1  =>  0 pairs (X)
E8,H8: 1.. / E8 = 1  =>  0 pairs (X) / H8 = 1  =>  0 pairs (_)
G6,G9: 1.. / G6 = 1  => 14 pairs (_) / G9 = 1  =>  0 pairs (X)
E1,F1: 2.. / E1 = 2  => 16 pairs (_) / F1 = 2  => 20 pairs (_)
C7,C9: 2.. / C7 = 2  => 15 pairs (_) / C9 = 2  =>  0 pairs (X)
C7,F7: 2.. / C7 = 2  => 15 pairs (_) / F7 = 2  =>  0 pairs (X)
E1,E9: 2.. / E1 = 2  => 16 pairs (_) / E9 = 2  => 20 pairs (_)
D2,F2: 3.. / D2 = 3  => 15 pairs (_) / F2 = 3  =>  0 pairs (X)
G6,I6: 3.. / G6 = 3  =>  0 pairs (X) / I6 = 3  => 15 pairs (_)
F8,I8: 3.. / F8 = 3  => 15 pairs (_) / I8 = 3  =>  0 pairs (X)
D2,D7: 3.. / D2 = 3  => 15 pairs (_) / D7 = 3  =>  0 pairs (X)
G6,G7: 3.. / G6 = 3  =>  0 pairs (X) / G7 = 3  => 15 pairs (_)
A1,A3: 4.. / A1 = 4  => 21 pairs (_) / A3 = 4  => 19 pairs (_)
H2,I2: 4.. / H2 = 4  => 15 pairs (_) / I2 = 4  => 20 pairs (_)
E5,F5: 4.. / E5 = 4  => 17 pairs (_) / F5 = 4  =>  0 pairs (X)
H7,I7: 4.. / H7 = 4  => 20 pairs (_) / I7 = 4  => 15 pairs (_)
A1,F1: 4.. / A1 = 4  => 21 pairs (_) / F1 = 4  => 19 pairs (_)
E3,E5: 4.. / E3 = 4  =>  0 pairs (X) / E5 = 4  => 17 pairs (_)
H2,H7: 4.. / H2 = 4  => 15 pairs (_) / H7 = 4  => 20 pairs (_)
I2,I7: 4.. / I2 = 4  => 20 pairs (_) / I7 = 4  => 15 pairs (_)
E2,E3: 5.. / E2 = 5  =>  0 pairs (X) / E3 = 5  => 18 pairs (_)
H4,I4: 5.. / H4 = 5  => 13 pairs (_) / I4 = 5  => 16 pairs (_)
F7,F9: 5.. / F7 = 5  => 16 pairs (_) / F9 = 5  => 15 pairs (_)
A1,G1: 5.. / A1 = 5  => 19 pairs (_) / G1 = 5  => 16 pairs (_)
F8,I8: 6.. / F8 = 6  =>  0 pairs (X) / I8 = 6  => 15 pairs (_)
D2,D3: 7.. / D2 = 7  =>  0 pairs (X) / D3 = 7  => 15 pairs (_)
H4,I4: 7.. / H4 = 7  => 16 pairs (_) / I4 = 7  => 13 pairs (_)
C8,C9: 7.. / C8 = 7  => 16 pairs (_) / C9 = 7  =>  0 pairs (X)
D3,G3: 7.. / D3 = 7  => 15 pairs (_) / G3 = 7  =>  0 pairs (X)
C8,H8: 7.. / C8 = 7  => 16 pairs (_) / H8 = 7  =>  0 pairs (X)
D1,E1: 8.. / D1 = 8  => 16 pairs (_) / E1 = 8  => 20 pairs (_)
H7,H9: 8.. / H7 = 8  => 16 pairs (_) / H9 = 8  => 18 pairs (_)
D7,H7: 8.. / D7 = 8  => 18 pairs (_) / H7 = 8  => 16 pairs (_)
E1,E9: 8.. / E1 = 8  => 20 pairs (_) / E9 = 8  => 16 pairs (_)
* DURATION: 0:00:59.451157  START: 17:15:10.266439  END: 17:16:09.717596 2017-05-04
* CP COUNT: (34)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,C7,C8,D1,D5,E1,E8,E9,F8,G1,H4,H6,I4,I6,I8)
* .76....31.28.......13....286912384..735...862284567...16..7....85.4..2..34.......
* PAIR A2: 5,9 BLK 1
A1: 5,9,4                                # reduction candidate for 5,9
A1: 5,9                                  # 19 pairs
A3: 5,9,4                                # reduction candidate for 5,9
A3: 5,9                                  # 21 pairs
* PAIR A2: 5,9 ROW 2
E2: 5,9,1                                # reduction candidate for 5,9
E2: 5,9 => CTR
* .76....31.283.16...137.6.286912384..7351..862284567...16..7....85.4132.634.6..71.
E2: 1 => SOLVED
* 476982531528316974913754628691238457735149862284567193162875349857493216349621785
G2: 5,9,6,7                              # reduction candidate for 5,9
G2: 5,9 => SOLVED
* 476982531528316974913754628691238457735149862284567193162875349857493216349621785
G2: 6,7                                  # 16 pairs
H2: 5,9,4,7                              # reduction candidate for 5,9
H2: 5,9 => CTR
* 476982531.283..794913754628691238457735149862284567.1.16287..4.85.4..2..34..2..8.
H2: 4,7                                  # 16 pairs
I2: 5,9,4,6,7                            # reduction candidate for 5,9
I2: 5,9 => CTR
* .76....31.2831674..1375.6286912384..73514986228456719316987.3.485749321634.6.1...
I2: 4,6,7                                # 15 pairs
* PAIR D1: 8,9 COL D
D7: 8,9,3                                # reduction candidate for 8,9
D7: 8,9                                  # 15 pairs
D9: 8,9,1,6                              # reduction candidate for 8,9
D9: 8,9 => CTR
* .76....31.28.13....13.5..286912384..735149862284567...16.37..8485.49621334.821...
D9: 1,6                                  # 16 pairs
* PAIR G1: 5,9 BLK 3
G2: 5,9,6,7                              # reduction candidate for 5,9
G2: 5,9 => SOLVED
* 476982531528316974913754628691238457735149862284567193162875349857493216349621785
G2: 6,7                                  # 16 pairs
H2: 5,9,4,7                              # reduction candidate for 5,9
H2: 5,9 => CTR
* 476982531.283..794913754628691238457735149862284567.1.16287..4.85.4..2..34..2..8.
H2: 4,7                                  # 16 pairs
I2: 5,9,4,6,7                            # reduction candidate for 5,9
I2: 5,9 => CTR
* .76....31.2831674..1375.6286912384..73514986228456719316987.3.485749321634.6.1...
I2: 4,6,7                                # 15 pairs
G3: 5,9,6,7                              # reduction candidate for 5,9
G3: 5,9 => CTR
* .769...31.283..6...137.6.286912384..7351..86228456719316..7.3..85749321634.6.17..
G3: 6,7                                  # 16 pairs
* PAIR G1: 5,9 ROW 1
A1: 5,9,4                                # reduction candidate for 5,9
A1: 4                                    # 21 pairs
A1: 5,9                                  # 19 pairs
* PAIR G1: 5,9 COL G
G7: 5,9,3                                # reduction candidate for 5,9
G7: 5,9 => CTR
* .76....31.28.......13....286912384..735...86228456731916..7....85.41.2..34....1..
G7: 3                                    # 15 pairs
G9: 5,9,1,6,7                            # reduction candidate for 5,9
G9: 5,9 => CTR
* .76982531.283167...1375.6286912384..73514986228456719316..753..85.49321634.621.87
G9: 1,6,7                                # 15 pairs
* PAIR D5: 1,9 BLK 5
E5: 1,9,4                                # reduction candidate for 1,9
E5: 1,9 => CTR
* 476...5319283516..5137469286912384..735..486228456719316..7.3..85.4.32.634.6..71.
E5: 4                                    # 17 pairs
F5: 1,9,4                                # reduction candidate for 1,9
F5: 1,9                                  # 17 pairs
* PAIR D5: 1,9 COL D
D2: 1,9,3,6,7                            # reduction candidate for 1,9
D2: 1,9 => CTR
* .76....31.28..3....137.6.286912384..735...862284567...16..7....85.4..2..34.......
D2: 3,6,7                                # 15 pairs
D9: 1,9,6,8                              # reduction candidate for 1,9
D9: 1,9 => CTR
* .7682..31.28.13....13.5..286912384..735.41862284567...16.37..8485.49621334.18....
D9: 6,8                                  # 16 pairs
* PAIR H4: 5,7 COL H
H2: 5,7,4,9                              # reduction candidate for 5,7
H2: 5,7 => SOLVED
* 476982531528316974913754628691238457735149862284567193162875349857493216349621785
H2: 4,9                                  # 16 pairs
H9: 5,7,1,8,9                            # reduction candidate for 5,7
H9: 5,7                                  # 18 pairs
* PAIR I4: 5,7 COL I
I2: 5,7,4,6,9                            # reduction candidate for 5,7
I2: 5,7                                  # 19 pairs
I9: 5,7,6,9                              # reduction candidate for 5,7
I9: 5,7                                  # 16 pairs
* PAIR H6: 1,9 BLK 6
G6: 1,9,3                                # reduction candidate for 1,9
G6: 3 => CTR
* .76....31.28.......13....286912384..735...86228456731916..7....85.41.2..34....1..
G6: 1,9                                  # 15 pairs
* PAIR H6: 1,9 COL H
H8: 1,9,7                                # reduction candidate for 1,9
H8: 1,9                                  # 16 pairs
H9: 1,9,5,7,8                            # reduction candidate for 1,9
H9: 1,9 => CTR
* .76....31.28...746.137.6.28691238457735...862284567...162.7..8485941327.347......
H9: 5,7,8                                # 15 pairs
* PAIR I6: 3,9 BLK 6
G6: 3,9,1                                # reduction candidate for 3,9
G6: 3,9 => CTR
* .76....31.28.......13....286912384..735...862284567.1.16..7....85.41.2..34....1..
G6: 1                                    # 14 pairs
* PAIR I6: 3,9 COL I
I7: 3,9,4,5                              # reduction candidate for 3,9
I7: 3,9                                  # 20 pairs
I7: 4,5                                  # 16 pairs
* PAIR C7: 2,9 BLK 7
C9: 2,9,7                                # reduction candidate for 2,9
C9: 7 => CTR
* .76....31.28...746.137.6.28691238457735...862284567...162.7...485941327.347......
C9: 2,9                                  # 16 pairs
* PAIR C7: 2,9 ROW 7
F7: 2,9,3,5                              # reduction candidate for 2,9
F7: 2,9                                  # 18 pairs
F7: 3,5                                  # 16 pairs
* PAIR C8: 7,9 BLK 7
C9: 7,9,2                                # reduction candidate for 7,9
C9: 2 => CTR
* 576824931928..3.45413.59.28691238457735.418622845673191693725848574.62.3342.85...
C9: 7,9                                  # 15 pairs
* PAIR C8: 7,9 ROW 8
H8: 7,9,1                                # reduction candidate for 7,9
H8: 7,9 => CTR
* .76....31.283.16...137.6.286912384..7351..862284567...16..7....85.4132.634.6..71.
H8: 1 => SOLVED
* 476982531528316974913754628691238457735149862284567193162875349857493216349621785
* PAIR E8: 1,9 BLK 8
D9: 1,9,6,8                              # reduction candidate for 1,9
D9: 1,9 => CTR
* .7682..31.28.13....13.5..286912384..735.41862284567...16.37..8485.49621334.18....
D9: 6,8                                  # 16 pairs
F9: 1,9,2,5,6                            # reduction candidate for 1,9
F9: 1,9                                  # 22 pairs
* PAIR E8: 1,9 ROW 8
H8: 1,9,7                                # reduction candidate for 1,9
H8: 7 => CTR
* .76....31.28...746.137.6.28691238457735...862284567...162.7...485941327.347......
H8: 1,9                                  # 16 pairs
* PAIR E8: 1,9 COL E
E2: 1,9,5                                # reduction candidate for 1,9
E2: 1,9                                  # 18 pairs
E5: 1,9,4                                # reduction candidate for 1,9
E5: 1,9 => CTR
* 476...5319283516..5137469286912384..735..486228456719316..7.3..85.4.32.634.6..71.
E5: 4                                    # 17 pairs
* PAIR F8: 3,6 COL F
F2: 3,6,1,9                              # reduction candidate for 3,6
F2: 3,6 => SOLVED
* 476982531528316974913754628691238457735149862284567193162875349857493216349621785
F2: 1,9 => CTR
* .769...31.283..6...137.6.286912384..7351..86228456719316..7.3..85749321634.6.17..
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-423-base-pr-000.dot
* REASONING
* DIS # E2: 5,9 => CTR => E2: 1
* PRF # E2: 1 => SOL
* PRF # G2: 5,9 => SOL
* DIS # H2: 5,9 => CTR => H2: 4,7
* DIS # I2: 5,9 => CTR => I2: 4,6,7
* DIS # D9: 8,9 => CTR => D9: 1,6
* PRF # G2: 5,9 => SOL
* DIS # H2: 5,9 => CTR => H2: 4,7
* DIS # I2: 5,9 => CTR => I2: 4,6,7
* DIS # G3: 5,9 => CTR => G3: 6,7
* DIS # G7: 5,9 => CTR => G7: 3
* DIS # G9: 5,9 => CTR => G9: 1,6,7
* DIS # E5: 1,9 => CTR => E5: 4
* DIS # D2: 1,9 => CTR => D2: 3,6,7
* DIS # D9: 1,9 => CTR => D9: 6,8
* PRF # H2: 5,7 => SOL
* DIS # G6: 3 => CTR => G6: 1,9
* DIS # H9: 1,9 => CTR => H9: 5,7,8
* DIS # G6: 3,9 => CTR => G6: 1
* DIS # C9: 7 => CTR => C9: 2,9
* DIS # C9: 2 => CTR => C9: 7,9
* DIS # H8: 7,9 => CTR => H8: 1
* PRF # H8: 1 => SOL
* DIS # D9: 1,9 => CTR => D9: 6,8
* DIS # H8: 7 => CTR => H8: 1,9
* DIS # E5: 1,9 => CTR => E5: 4
* PRF # F2: 3,6 => SOL
* DIS # F2: 1,9 => CTR => F2: 3,6
* CNT  28 HDP CHAINS /  66 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,C7,C8,D1,D5,E1,E8,E9,F8,G1,H4,H6,I4,I6,I8)
* .76....31.28.......13....286912384..735...862284567...16..7....85.4..2..34.......
* PAIR A2: 5,9 BLK 1
A1: 5,9,4                                # reduction candidate for 5,9
A1: 5,9                                  # 19 pairs
A3: 5,9,4                                # reduction candidate for 5,9
A3: 5,9                                  # 21 pairs
* PAIR A2: 5,9 ROW 2
E2: 5,9,1                                # reduction candidate for 5,9
E2: 5,9 => CTR
* .76....31.283.16...137.6.286912384..7351..862284567...16..7....85.4132.634.6..71.
E2: 1 => SOLVED
* 476982531528316974913754628691238457735149862284567193162875349857493216349621785
* DURATION: 0:00:03.808163  START: 17:17:13.477356  END: 17:17:17.285519 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-423-base-pr-001.dot
* REASONING
* DIS # E2: 5,9 => CTR => E2: 1
* PRF E2: 1 => SOL
* STA E2: 1
* CNT   2 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 423

solution: 476982531528316974913754628691238457735149862284567193162875349857493216349621785
info: 95136    FNBHYK   S8.f     210

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

Solution

position: 476982531528316974913754628691238457735149862284567193162875349857493216349621785 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 # A1: 5,9 => UNS
* INC # A3: 5,9 => UNS
* DIS # E2: 5,9 => CTR => E2: 1
* PRF # E2: 1 => SOL
* PRF # G2: 5,9 => SOL
* INC # G2: 6,7 => UNS
* DIS # H2: 5,9 => CTR => H2: 4,7
* INC # H2: 4,7 => UNS
* DIS # I2: 5,9 => CTR => I2: 4,6,7
* INC # I2: 4,6,7 => UNS
* INC # D7: 8,9 => UNS
* DIS # D9: 8,9 => CTR => D9: 1,6
* INC # D9: 1,6 => UNS
* PRF # G2: 5,9 => SOL
* INC # G2: 6,7 => UNS
* DIS # H2: 5,9 => CTR => H2: 4,7
* INC # H2: 4,7 => UNS
* DIS # I2: 5,9 => CTR => I2: 4,6,7
* INC # I2: 4,6,7 => UNS
* DIS # G3: 5,9 => CTR => G3: 6,7
* INC # G3: 6,7 => UNS
* INC # A1: 5,9 => UNS
* INC # A1: 4 => UNS
* DIS # G7: 5,9 => CTR => G7: 3
* INC # G7: 3 => UNS
* DIS # G9: 5,9 => CTR => G9: 1,6,7
* INC # G9: 1,6,7 => UNS
* DIS # E5: 1,9 => CTR => E5: 4
* INC # E5: 4 => UNS
* INC # F5: 1,9 => UNS
* DIS # D2: 1,9 => CTR => D2: 3,6,7
* INC # D2: 3,6,7 => UNS
* DIS # D9: 1,9 => CTR => D9: 6,8
* INC # D9: 6,8 => UNS
* PRF # H2: 5,7 => SOL
* INC # H2: 4,9 => UNS
* INC # H9: 5,7 => UNS
* INC # I2: 5,7 => UNS
* INC # I9: 5,7 => UNS
* INC # G6: 1,9 => UNS
* DIS # G6: 3 => CTR => G6: 1,9
* INC # H8: 1,9 => UNS
* DIS # H9: 1,9 => CTR => H9: 5,7,8
* INC # H9: 5,7,8 => UNS
* DIS # G6: 3,9 => CTR => G6: 1
* INC # G6: 1 => UNS
* INC # I7: 3,9 => UNS
* INC # I7: 4,5 => UNS
* INC # C9: 2,9 => UNS
* DIS # C9: 7 => CTR => C9: 2,9
* INC # F7: 2,9 => UNS
* INC # F7: 3,5 => UNS
* INC # C9: 7,9 => UNS
* DIS # C9: 2 => CTR => C9: 7,9
* DIS # H8: 7,9 => CTR => H8: 1
* PRF # H8: 1 => SOL
* DIS # D9: 1,9 => CTR => D9: 6,8
* INC # D9: 6,8 => UNS
* INC # F9: 1,9 => UNS
* INC # H8: 1,9 => UNS
* DIS # H8: 7 => CTR => H8: 1,9
* INC # E2: 1,9 => UNS
* DIS # E5: 1,9 => CTR => E5: 4
* INC # E5: 4 => UNS
* PRF # F2: 3,6 => SOL
* DIS # F2: 1,9 => CTR => F2: 3,6
* CNT  66 HDP CHAINS /  66 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A1: 5,9 => UNS
* INC # A3: 5,9 => UNS
* DIS # E2: 5,9 => CTR => E2: 1
* PRF E2: 1 => SOL
* STA E2: 1
* CNT   4 HDP CHAINS /   3 HYP OPENED