Analysis of xx-top500-418-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....1..632.9..................9.51.....28.....3.......5.....9...6..3.......8...4. initial

Autosolve

position: .5..192632.9368...3.6.52...6..9.513..9.2836...3.6.1...5.312.9.696.53.......896345 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # B3: 4,7 => SOL
* DIS # I3: 4,7 => CTR => I3: 1,8,9
* DIS # I4: 4,7 => CTR => I4: 2,8
* DIS # C6: 4,7 => CTR => C6: 2,5,8
* DIS # I6: 4,7 => CTR => I6: 2,8,9
* DIS # H6: 5,7 => CTR => H6: 2,8,9
* PRF # H2: 5,7 => SOL
* DIS # I4: 4,7 => CTR => I4: 2,8
* DIS # I6: 4,7 => CTR => I6: 2,8,9
* DIS # I3: 4,7 => CTR => I3: 1,8,9
* DIS # B4: 2,7 => CTR => B4: 4,8
* DIS # C4: 4,8 => CTR => C4: 2,7
* DIS # C6: 4,8 => CTR => C6: 2,5,7
* DIS # C9: 2 => CTR => C9: 1,7
* DIS # B4: 2,7 => CTR => B4: 4,8
* DIS # H6: 7,8 => CTR => H6: 2,5,9
* DIS # G6: 7,8 => CTR => G6: 4,5
* CNT  17 HDP CHAINS /  55 HYP OPENED

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

Pair Reduction

Pair Reduction

The following important HDP chains were detected:

* PRF # B3: 4,7 => SOL
* STA B3: 4,7
* CNT   1 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

....1..632.9..................9.51.....28.....3.......5.....9...6..3.......8...4. initial
.5..192632.9368...3.6.52...6..9.513..9.2836...3.6.1...5.312.9.696.53.......896345 autosolve
854719263219368457376452819687945132195283674432671598543127986968534721721896345 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (16)
D1: 4,7
D3: 4,7
E4: 4,7
E6: 4,7
H5: 5,7
I5: 4,7
B7: 4,8
C8: 4,8
A9: 1,7
B9: 2,7
F7: 4,7
F8: 4,7
H7: 7,8
G8: 7,8
H8: 1,2
I8: 1,2

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B2,B3: 1.. / B2 = 1  =>  0 pairs (*) / B3 = 1  =>  0 pairs (X)
A5,C5: 1.. / A5 = 1  => 16 pairs (_) / C5 = 1  => 19 pairs (_)
A9,C9: 1.. / A9 = 1  => 19 pairs (_) / C9 = 1  => 16 pairs (_)
H8,I8: 1.. / H8 = 1  =>  0 pairs (X) / I8 = 1  => 17 pairs (_)
A5,A9: 1.. / A5 = 1  => 16 pairs (_) / A9 = 1  => 19 pairs (_)
C5,C9: 1.. / C5 = 1  => 19 pairs (_) / C9 = 1  => 16 pairs (_)
B9,C9: 2.. / B9 = 2  => 16 pairs (_) / C9 = 2  =>  0 pairs (X)
H8,I8: 2.. / H8 = 2  => 17 pairs (_) / I8 = 2  =>  0 pairs (X)
B4,B9: 2.. / B4 = 2  =>  0 pairs (X) / B9 = 2  => 16 pairs (_)
H6,H8: 2.. / H6 = 2  =>  0 pairs (X) / H8 = 2  => 17 pairs (_)
D1,D3: 4.. / D1 = 4  =>  0 pairs (X) / D3 = 4  => 26 pairs (_)
E4,E6: 4.. / E4 = 4  => 15 pairs (_) / E6 = 4  => 16 pairs (_)
B7,C8: 4.. / B7 = 4  =>  0 pairs (*) / C8 = 4  =>  0 pairs (X)
F7,F8: 4.. / F7 = 4  => 14 pairs (_) / F8 = 4  =>  0 pairs (*)
B7,F7: 4.. / B7 = 4  =>  0 pairs (*) / F7 = 4  =>  0 pairs (X)
C8,F8: 4.. / C8 = 4  => 14 pairs (_) / F8 = 4  =>  0 pairs (*)
G2,H2: 5.. / G2 = 5  => 19 pairs (_) / H2 = 5  =>  0 pairs (*)
C5,C6: 5.. / C5 = 5  =>  0 pairs (*) / C6 = 5  =>  0 pairs (X)
C5,H5: 5.. / C5 = 5  =>  0 pairs (*) / H5 = 5  =>  0 pairs (X)
G2,G6: 5.. / G2 = 5  => 19 pairs (_) / G6 = 5  =>  0 pairs (*)
D1,D3: 7.. / D1 = 7  => 26 pairs (_) / D3 = 7  =>  0 pairs (X)
E4,E6: 7.. / E4 = 7  => 16 pairs (_) / E6 = 7  => 15 pairs (_)
F7,F8: 7.. / F7 = 7  =>  0 pairs (*) / F8 = 7  =>  0 pairs (X)
H7,G8: 7.. / H7 = 7  => 14 pairs (_) / G8 = 7  =>  0 pairs (*)
F7,H7: 7.. / F7 = 7  =>  0 pairs (*) / H7 = 7  =>  0 pairs (X)
F8,G8: 7.. / F8 = 7  => 14 pairs (_) / G8 = 7  =>  0 pairs (*)
A1,C1: 8.. / A1 = 8  => 20 pairs (_) / C1 = 8  => 14 pairs (_)
B7,C8: 8.. / B7 = 8  => 14 pairs (_) / C8 = 8  =>  0 pairs (*)
H7,G8: 8.. / H7 = 8  =>  0 pairs (*) / G8 = 8  =>  0 pairs (X)
B7,H7: 8.. / B7 = 8  => 14 pairs (_) / H7 = 8  =>  0 pairs (*)
C8,G8: 8.. / C8 = 8  =>  0 pairs (*) / G8 = 8  =>  0 pairs (X)
A1,A6: 8.. / A1 = 8  => 20 pairs (_) / A6 = 8  => 14 pairs (_)
B4,B7: 8.. / B4 = 8  =>  0 pairs (*) / B7 = 8  =>  0 pairs (X)
H3,I3: 9.. / H3 = 9  => 16 pairs (_) / I3 = 9  => 17 pairs (_)
H6,I6: 9.. / H6 = 9  => 17 pairs (_) / I6 = 9  => 16 pairs (_)
H3,H6: 9.. / H3 = 9  => 16 pairs (_) / H6 = 9  => 17 pairs (_)
I3,I6: 9.. / I3 = 9  => 17 pairs (_) / I6 = 9  => 16 pairs (_)
* DURATION: 0:01:07.749797  START: 17:06:29.763375  END: 17:07:37.513172 2017-05-04
* CP COUNT: (37)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A9,B7,B9,C8,D1,D3,E4,E6,F7,F8,G8,H5,H7,H8,I5,I8)
* .5..192632.9368...3.6.52...6..9.513..9.2836...3.6.1...5.312.9.696.53.......896345
* PAIR D1: 4,7 ROW 1
A1: 4,7,8                                # reduction candidate for 4,7
A1: 4,7                                  # 14 pairs
C1: 4,7,8                                # reduction candidate for 4,7
C1: 4,7                                  # 20 pairs
* PAIR D3: 4,7 ROW 3
B3: 4,7,1                                # reduction candidate for 4,7
B3: 4,7 => SOLVED
* 854719263219368457376452819687945132195283674432671598543127986968534721721896345
B3: 1                                    # 17 pairs
G3: 4,7,8                                # reduction candidate for 4,7
G3: 4,7                                  # 20 pairs
I3: 4,7,1,8,9                            # reduction candidate for 4,7
I3: 4,7 => CTR
* .5..192632.9368...316.5289.6..9.5138.9.2836...3.6.1.2958312497696.53.......896345
I3: 1,8,9                                # 16 pairs
* PAIR E4: 4,7 ROW 4
B4: 4,7,2,8                              # reduction candidate for 4,7
B4: 4,7                                  # 14 pairs
C4: 4,7,2,8                              # reduction candidate for 4,7
C4: 4,7                                  # 22 pairs
I4: 4,7,2,8                              # reduction candidate for 4,7
I4: 4,7 => CTR
* 8547192632.93685.1316.524.86..9.513..9.28365..356.18.95.312.986968534712...896345
I4: 2,8                                  # 17 pairs
* PAIR E6: 4,7 ROW 6
A6: 4,7,8                                # reduction candidate for 4,7
A6: 4,7                                  # 20 pairs
C6: 4,7,2,5,8                            # reduction candidate for 4,7
C6: 4,7 => CTR
* 85..192632.9368...3.6.52...6829.513..95283674.3.6.1...5.31279869685347....1896345
C6: 2,5,8                                # 16 pairs
G6: 4,7,5,8                              # reduction candidate for 4,7
G6: 4,7                                  # 14 pairs
I6: 4,7,2,8,9                            # reduction candidate for 4,7
I6: 4,7 => CTR
* .5..192632.9368...3.6.52..96..9.5138.9.2836...3.6.1...5.312.9.696.53.......896345
I6: 2,8,9                                # 16 pairs
* PAIR H5: 5,7 BLK 6
G6: 5,7,4,8                              # reduction candidate for 5,7
G6: 5,7                                  # 24 pairs
H6: 5,7,2,8,9                            # reduction candidate for 5,7
H6: 5,7 => CTR
* 85471926327936851.316.52.9.68.9.5132.9.2836...326.1859543127986968534721.2.896345
H6: 2,8,9                                # 16 pairs
* PAIR H5: 5,7 ROW 5
C5: 5,7,1,4                              # reduction candidate for 5,7
C5: 1,4                                  # 19 pairs
C5: 5,7                                  # 17 pairs
* PAIR H5: 5,7 COL H
H2: 5,7,1                                # reduction candidate for 5,7
H2: 5,7 => SOLVED
* 854719263219368457376452819687945132195283674432671598543127986968534721721896345
H2: 1                                    # 21 pairs
* PAIR I5: 4,7 BLK 6
I4: 4,7,2,8                              # reduction candidate for 4,7
I4: 4,7 => CTR
* 8547192632.93685.1316.524.86..9.513..9.28365..356.18.95.312.986968534712...896345
I4: 2,8                                  # 17 pairs
G6: 4,7,5,8                              # reduction candidate for 4,7
G6: 4,7                                  # 14 pairs
I6: 4,7,2,8,9                            # reduction candidate for 4,7
I6: 4,7 => CTR
* .5..192632.9368...3.6.52..96..9.5138.9.2836...3.6.1...5.312.9.696.53.......896345
I6: 2,8,9                                # 16 pairs
* PAIR I5: 4,7 ROW 5
A5: 4,7,1                                # reduction candidate for 4,7
A5: 4,7                                  # 19 pairs
C5: 4,7,1,5                              # reduction candidate for 4,7
C5: 4,7                                  # 19 pairs
* PAIR I5: 4,7 COL I
I2: 4,7,1                                # reduction candidate for 4,7
I2: 4,7                                  # 18 pairs
I3: 4,7,1,8,9                            # reduction candidate for 4,7
I3: 4,7 => CTR
* .5..192632.9368...316.5289.6..9.5138.9.2836...3.6.1.2958312497696.53.......896345
I3: 1,8,9                                # 16 pairs
* PAIR B7: 4,8 COL B
B4: 4,8,2,7                              # reduction candidate for 4,8
B4: 2,7 => CTR
* .5..192632493685173167524..6..9.513..9.283654435671...583124976964537821...896345
B4: 4,8                                  # 26 pairs
* PAIR C8: 4,8 COL C
C1: 4,8,7                                # reduction candidate for 4,8
C1: 4,8                                  # 18 pairs
C4: 4,8,2,7                              # reduction candidate for 4,8
C4: 4,8 => CTR
* 8574192632.9368...3.67524..6.89.513..9.28365..356.17..5831249769645378....2896345
C4: 2,7                                  # 17 pairs
C6: 4,8,2,5,7                            # reduction candidate for 4,8
C6: 4,8 => CTR
* 85..192632.9368...3.6.52...6829.513..95283674.3.6.1...5.31279869685347....1896345
C6: 2,5,7                                # 16 pairs
* PAIR A9: 1,7 BLK 7
C9: 1,7,2                                # reduction candidate for 1,7
C9: 2 => CTR
* .5..192632.93685173167524..62.9.513.791283654435671...5831249769645378..172896345
C9: 1,7                                  # 16 pairs
* PAIR A9: 1,7 COL A
A5: 1,7,4                                # reduction candidate for 1,7
A5: 4                                    # 22 pairs
A5: 1,7                                  # 19 pairs
* PAIR B9: 2,7 BLK 7
C9: 2,7,1                                # reduction candidate for 2,7
C9: 2,7                                  # 19 pairs
C9: 1                                    # 16 pairs
* PAIR B9: 2,7 COL B
B4: 2,7,4,8                              # reduction candidate for 2,7
B4: 2,7 => CTR
* .5..192632493685173167524..6..9.513..9.283654435671...583124976964537821...896345
B4: 4,8                                  # 26 pairs
* PAIR H7: 7,8 COL H
H3: 7,8,1,9                              # reduction candidate for 7,8
H3: 7,8                                  # 14 pairs
H6: 7,8,2,5,9                            # reduction candidate for 7,8
H6: 7,8 => CTR
* .5..192632.9368.1.316.52.9.6..9.5132.9.28365..3.6.1..95.312.9.696.53..21...896345
H6: 2,5,9                                # 16 pairs
* PAIR G8: 7,8 COL G
G3: 7,8,4                                # reduction candidate for 7,8
G3: 7,8                                  # 21 pairs
G6: 7,8,4,5                              # reduction candidate for 7,8
G6: 7,8 => CTR
* .5.4192632493685173167524..6..9.513..9.283654435671...5831249769645378.....896345
G6: 4,5                                  # 19 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-418-base-pr-000.dot
* REASONING
* PRF # B3: 4,7 => SOL
* DIS # I3: 4,7 => CTR => I3: 1,8,9
* DIS # I4: 4,7 => CTR => I4: 2,8
* DIS # C6: 4,7 => CTR => C6: 2,5,8
* DIS # I6: 4,7 => CTR => I6: 2,8,9
* DIS # H6: 5,7 => CTR => H6: 2,8,9
* PRF # H2: 5,7 => SOL
* DIS # I4: 4,7 => CTR => I4: 2,8
* DIS # I6: 4,7 => CTR => I6: 2,8,9
* DIS # I3: 4,7 => CTR => I3: 1,8,9
* DIS # B4: 2,7 => CTR => B4: 4,8
* DIS # C4: 4,8 => CTR => C4: 2,7
* DIS # C6: 4,8 => CTR => C6: 2,5,7
* DIS # C9: 2 => CTR => C9: 1,7
* DIS # B4: 2,7 => CTR => B4: 4,8
* DIS # H6: 7,8 => CTR => H6: 2,5,9
* DIS # G6: 7,8 => CTR => G6: 4,5
* CNT  17 HDP CHAINS /  55 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A9,B7,B9,C8,D1,D3,E4,E6,F7,F8,G8,H5,H7,H8,I5,I8)
* .5..192632.9368...3.6.52...6..9.513..9.2836...3.6.1...5.312.9.696.53.......896345
* PAIR D1: 4,7 ROW 1
A1: 4,7,8                                # reduction candidate for 4,7
A1: 4,7                                  # 14 pairs
C1: 4,7,8                                # reduction candidate for 4,7
C1: 4,7                                  # 20 pairs
* PAIR D3: 4,7 ROW 3
B3: 4,7,1                                # reduction candidate for 4,7
B3: 4,7 => SOLVED
* 854719263219368457376452819687945132195283674432671598543127986968534721721896345
* DURATION: 0:00:04.793384  START: 17:08:32.743049  END: 17:08:37.536433 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-418-base-pr-001.dot
* REASONING
* PRF # B3: 4,7 => SOL
* STA B3: 4,7
* CNT   1 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 418

solution: 854719263219368457376452819687945132195283674432671598543127986968534721721896345
info: 95090    FNBTYK   S8.f     2717

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

Solution

position: 854719263219368457376452819687945132195283674432671598543127986968534721721896345 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: 4,7 => UNS
* INC # C1: 4,7 => UNS
* PRF # B3: 4,7 => SOL
* INC # B3: 1 => UNS
* INC # G3: 4,7 => UNS
* DIS # I3: 4,7 => CTR => I3: 1,8,9
* INC # I3: 1,8,9 => UNS
* INC # B4: 4,7 => UNS
* INC # C4: 4,7 => UNS
* DIS # I4: 4,7 => CTR => I4: 2,8
* INC # I4: 2,8 => UNS
* INC # A6: 4,7 => UNS
* DIS # C6: 4,7 => CTR => C6: 2,5,8
* INC # C6: 2,5,8 => UNS
* INC # G6: 4,7 => UNS
* DIS # I6: 4,7 => CTR => I6: 2,8,9
* INC # I6: 2,8,9 => UNS
* INC # G6: 5,7 => UNS
* DIS # H6: 5,7 => CTR => H6: 2,8,9
* INC # H6: 2,8,9 => UNS
* INC # C5: 5,7 => UNS
* INC # C5: 1,4 => UNS
* PRF # H2: 5,7 => SOL
* INC # H2: 1 => UNS
* DIS # I4: 4,7 => CTR => I4: 2,8
* INC # I4: 2,8 => UNS
* INC # G6: 4,7 => UNS
* DIS # I6: 4,7 => CTR => I6: 2,8,9
* INC # I6: 2,8,9 => UNS
* INC # A5: 4,7 => UNS
* INC # C5: 4,7 => UNS
* INC # I2: 4,7 => UNS
* DIS # I3: 4,7 => CTR => I3: 1,8,9
* INC # I3: 1,8,9 => UNS
* INC # B4: 4,8 => UNS
* DIS # B4: 2,7 => CTR => B4: 4,8
* INC # C1: 4,8 => UNS
* DIS # C4: 4,8 => CTR => C4: 2,7
* INC # C4: 2,7 => UNS
* DIS # C6: 4,8 => CTR => C6: 2,5,7
* INC # C6: 2,5,7 => UNS
* INC # C9: 1,7 => UNS
* DIS # C9: 2 => CTR => C9: 1,7
* INC # A5: 1,7 => UNS
* INC # A5: 4 => UNS
* INC # C9: 2,7 => UNS
* INC # C9: 1 => UNS
* DIS # B4: 2,7 => CTR => B4: 4,8
* INC # B4: 4,8 => UNS
* INC # H3: 7,8 => UNS
* DIS # H6: 7,8 => CTR => H6: 2,5,9
* INC # H6: 2,5,9 => UNS
* INC # G3: 7,8 => UNS
* DIS # G6: 7,8 => CTR => G6: 4,5
* INC # G6: 4,5 => UNS
* CNT  55 HDP CHAINS /  55 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A1: 4,7 => UNS
* INC # C1: 4,7 => UNS
* PRF # B3: 4,7 => SOL
* STA B3: 4,7
* CNT   3 HDP CHAINS /   3 HYP OPENED