Analysis of xx-top500-091-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .4..1..........3.........7...35.2...6......1....7....43.....7...16.........8..5.. initial

Autosolve

position: 74.613.5..61...34..3.4..1761.35426.76743..215...761.343..1.476..16...4.34.78365.1 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # E2: 2,9 => CTR => E2: 5,7,8
* DIS # A2: 2,9 => CTR => A2: 5,8
* PRF # I1: 8,9 => SOL
* PRF # C1: 2 => SOL
* DIS # B6: 8,9 => CTR => B6: 2,5
* DIS # B7: 8,9 => CTR => B7: 2,5
* PRF # H8: 8,9 => SOL
* DIS # H8: 2 => CTR => H8: 8,9
* DIS # B6: 8,9 => CTR => B6: 2,5
* PRF # B7: 2,9 => SOL
* DIS # A8: 2,9 => CTR => A8: 5,8
* DIS # B6: 2,9 => CTR => B6: 5,8
* PRF # E8: 2,9 => SOL
* DIS # A8: 2,9 => CTR => A8: 5,8
* DIS # H8: 2,9 => CTR => H8: 8
* PRF # H8: 8 => SOL
* PRF # H8: 8,9 => SOL
* DIS # H8: 2 => CTR => H8: 8,9
* DIS # B7: 8,9 => CTR => B7: 2,5
* PRF # I1: 8,9 => SOL
* DIS # H8: 2,9 => CTR => H8: 8
* PRF # H8: 8 => SOL
* CNT  22 HDP CHAINS /  51 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: 2,9 => CTR => E2: 5,7,8
* DIS E2: 5,7,8 # A2: 2,9 => CTR => A2: 5,8
* DIS E2: 5,7,8 + A2: 5,8 # I2: 8 => CTR => I2: 2,9
* DIS E2: 5,7,8 + A2: 5,8 + I2: 2,9 # E3: 5,8 => CTR => E3: 2,9
* PRF E2: 5,7,8 + A2: 5,8 + I2: 2,9 + E3: 2,9 # I1: 8,9 => SOL
* STA E2: 5,7,8 + A2: 5,8 + I2: 2,9 + E3: 2,9 + I1: 8,9
* CNT   5 HDP CHAINS /  11 HYP OPENED

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

Details

Positions

.4..1..........3.........7...35.2...6......1....7....43.....7...16.........8..5.. initial
74.613.5..61...34..3.4..1761.35426.76743..215...761.343..1.476..16...4.34.78365.1 autosolve
742613958861975342935428176183542697674389215259761834328154769516297483497836521 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (11)
D2: 2,9
G1: 8,9
B4: 8,9
E5: 8,9
F5: 8,9
H4: 8,9
G6: 8,9
B9: 2,9
D8: 2,9
I7: 8,9
H9: 2,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
I1,I2: 2.. / I1 = 2  => 13 pairs (_) / I2 = 2  =>  0 pairs (*)
H8,H9: 2.. / H8 = 2  =>  0 pairs (X) / H9 = 2  =>  0 pairs (_)
C1,I1: 2.. / C1 = 2  =>  0 pairs (*) / I1 = 2  =>  0 pairs (X)
B9,H9: 2.. / B9 = 2  =>  0 pairs (X) / H9 = 2  =>  0 pairs (_)
D2,D8: 2.. / D2 = 2  => 14 pairs (_) / D8 = 2  =>  0 pairs (*)
B6,B7: 5.. / B6 = 5  => 11 pairs (_) / B7 = 5  => 14 pairs (_)
E2,F2: 7.. / E2 = 7  => 11 pairs (_) / F2 = 7  => 12 pairs (_)
E8,F8: 7.. / E8 = 7  => 12 pairs (_) / F8 = 7  => 11 pairs (_)
E2,E8: 7.. / E2 = 7  => 11 pairs (_) / E8 = 7  => 12 pairs (_)
F2,F8: 7.. / F2 = 7  => 12 pairs (_) / F8 = 7  => 11 pairs (_)
E5,F5: 8.. / E5 = 8  => 11 pairs (_) / F5 = 8  => 12 pairs (_)
H4,G6: 8.. / H4 = 8  =>  0 pairs (X) / G6 = 8  =>  0 pairs (_)
I7,H8: 8.. / I7 = 8  =>  0 pairs (X) / H8 = 8  =>  0 pairs (_)
B4,H4: 8.. / B4 = 8  =>  0 pairs (*) / H4 = 8  =>  0 pairs (X)
A8,H8: 8.. / A8 = 8  =>  0 pairs (X) / H8 = 8  =>  0 pairs (_)
G1,G6: 8.. / G1 = 8  =>  0 pairs (X) / G6 = 8  =>  0 pairs (_)
H4,H8: 8.. / H4 = 8  =>  0 pairs (X) / H8 = 8  =>  0 pairs (_)
E5,F5: 9.. / E5 = 9  => 12 pairs (_) / F5 = 9  => 11 pairs (_)
H4,G6: 9.. / H4 = 9  =>  0 pairs (*) / G6 = 9  =>  0 pairs (X)
B4,H4: 9.. / B4 = 9  =>  0 pairs (X) / H4 = 9  =>  0 pairs (_)
B9,H9: 9.. / B9 = 9  =>  0 pairs (*) / H9 = 9  =>  0 pairs (X)
D2,D8: 9.. / D2 = 9  =>  0 pairs (*) / D8 = 9  =>  0 pairs (X)
G1,G6: 9.. / G1 = 9  =>  0 pairs (*) / G6 = 9  =>  0 pairs (X)
* DURATION: 0:00:39.571521  START: 05:53:25.962712  END: 05:54:05.534233 2017-05-04
* CP COUNT: (23)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B4,B9,D2,D8,E5,F5,G1,G6,H4,H9,I7)
* 74.613.5..61...34..3.4..1761.35426.76743..215...761.343..1.476..16...4.34.78365.1
* PAIR D2: 2,9 BLK 2
E2: 2,9,5,7,8                            # reduction candidate for 2,9
E2: 2,9 => CTR
* 748613952561..7348.3.458176183542697674389215...7618343..124769216975483497836521
E2: 5,7,8                                # 11 pairs
E3: 2,9,5,8                              # reduction candidate for 2,9
E3: 2,9                                  # 13 pairs
* PAIR D2: 2,9 ROW 2
A2: 2,9,5,8                              # reduction candidate for 2,9
A2: 2,9 => CTR
* 748613952.61...348.3.4..1761835426976743..215...7618343..1.4769.16...483497836521
A2: 5,8                                  # 12 pairs
I2: 2,9,8                                # reduction candidate for 2,9
I2: 2,9                                  # 14 pairs
* PAIR G1: 8,9 BLK 3
I1: 8,9,2                                # reduction candidate for 8,9
I1: 8,9 => SOLVED
* 742613958861975342935428176183542697674389215259761834328154769516297483497836521
I1: 2                                    # 13 pairs
I2: 8,9,2                                # reduction candidate for 8,9
I2: 8,9                                  # 13 pairs
* PAIR G1: 8,9 ROW 1
C1: 8,9,2                                # reduction candidate for 8,9
C1: 2 => SOLVED
* 742613958861975342935428176183542697674389215259761834328154769516297483497836521
C1: 8,9                                  # 13 pairs
* PAIR B4: 8,9 BLK 4
A6: 8,9,2,5                              # reduction candidate for 8,9
A6: 8,9                                  # 14 pairs
B6: 8,9,2,5                              # reduction candidate for 8,9
B6: 8,9 => CTR
* 74.61385..612..34993.4..1761935426876743..215.8.76193435.1247688169..423427836591
B6: 2,5                                  # 12 pairs
C6: 8,9,2,5                              # reduction candidate for 8,9
C6: 8,9                                  # 14 pairs
* PAIR B4: 8,9 COL B
B7: 8,9,2,5                              # reduction candidate for 8,9
B7: 8,9 => CTR
* 74.613.5..61...34..3.4..1761935426876743..215.5.76193438.1.476..16...4.3427836591
B7: 2,5                                  # 12 pairs
* PAIR E5: 8,9 COL E
E2: 8,9,2,5,7                            # reduction candidate for 8,9
E2: 8,9                                  # 15 pairs
E3: 8,9,2,5                              # reduction candidate for 8,9
E3: 8,9                                  # 16 pairs
* PAIR F5: 8,9 COL F
F2: 8,9,5,7                              # reduction candidate for 8,9
F2: 8,9                                  # 13 pairs
F3: 8,9,5                                # reduction candidate for 8,9
F3: 8,9                                  # 14 pairs
* PAIR H4: 8,9 COL H
H8: 8,9,2                                # reduction candidate for 8,9
H8: 8,9 => SOLVED
* 742613958861975342935428176183542697674389215259761834328154769516297483497836521
H8: 2 => CTR
* 74.61385..612..34993.4..1761.35426876743..215...7619343..1.4768816...423427836591
* PAIR G6: 8,9 ROW 6
A6: 8,9,2,5                              # reduction candidate for 8,9
A6: 8,9                                  # 14 pairs
B6: 8,9,2,5                              # reduction candidate for 8,9
B6: 8,9 => CTR
* 74.61385..612..34993.4..1761935426876743..215.8.76193435.1247688169..423427836591
B6: 2,5                                  # 12 pairs
C6: 8,9,2,5                              # reduction candidate for 8,9
C6: 8,9                                  # 14 pairs
* PAIR B9: 2,9 BLK 7
B7: 2,9,5,8                              # reduction candidate for 2,9
B7: 2,9 => SOLVED
* 742613958861975342935428176183542697674389215259761834328154769516297483497836521
B7: 5,8                                  # 12 pairs
C7: 2,9,5,8                              # reduction candidate for 2,9
C7: 2,9                                  # 14 pairs
A8: 2,9,5,8                              # reduction candidate for 2,9
A8: 2,9 => CTR
* 74.613958.61...342.3.42.1761835426976743..215...7618343.81.4769.16...483497836521
A8: 5,8                                  # 12 pairs
* PAIR B9: 2,9 COL B
B6: 2,9,5,8                              # reduction candidate for 2,9
B6: 2,9 => CTR
* 742613958.612..34..3.4..1761835426976743..215.2.7618343581247692169..483497836521
B6: 5,8                                  # 12 pairs
* PAIR D8: 2,9 BLK 8
E7: 2,9,5                                # reduction candidate for 2,9
E7: 2,9                                  # 14 pairs
E8: 2,9,5,7                              # reduction candidate for 2,9
E8: 2,9 => SOLVED
* 742613958861975342935428176183542697674389215259761834328154769516297483497836521
E8: 5,7                                  # 12 pairs
* PAIR D8: 2,9 ROW 8
A8: 2,9,5,8                              # reduction candidate for 2,9
A8: 2,9 => CTR
* 74.613958.61...342.3.42.1761835426976743..215...7618343.81.4769.16...483497836521
A8: 5,8                                  # 12 pairs
H8: 2,9,8                                # reduction candidate for 2,9
H8: 2,9 => CTR
* 742613859.612..34..384..1761935426876743..215.8.7619343591247688169..423427836591
H8: 8 => SOLVED
* 742613958861975342935428176183542697674389215259761834328154769516297483497836521
* PAIR I7: 8,9 BLK 9
H8: 8,9,2                                # reduction candidate for 8,9
H8: 8,9 => SOLVED
* 742613958861975342935428176183542697674389215259761834328154769516297483497836521
H8: 2 => CTR
* 74.61385..612..34993.4..1761.35426876743..215...7619343..1.4768816...423427836591
* PAIR I7: 8,9 ROW 7
B7: 8,9,2,5                              # reduction candidate for 8,9
B7: 8,9 => CTR
* 74.613.5..61...34..3.4..1761935426876743..215.5.76193438.1.476..16...4.3427836591
B7: 2,5                                  # 12 pairs
C7: 8,9,2,5                              # reduction candidate for 8,9
C7: 8,9                                  # 15 pairs
* PAIR I7: 8,9 COL I
I1: 8,9,2                                # reduction candidate for 8,9
I1: 8,9 => SOLVED
* 742613958861975342935428176183542697674389215259761834328154769516297483497836521
I1: 2                                    # 13 pairs
I2: 8,9,2                                # reduction candidate for 8,9
I2: 8,9                                  # 13 pairs
* PAIR H9: 2,9 BLK 9
H8: 2,9,8                                # reduction candidate for 2,9
H8: 2,9 => CTR
* 742613859.612..34..384..1761935426876743..215.8.7619343591247688169..423427836591
H8: 8 => SOLVED
* 742613958861975342935428176183542697674389215259761834328154769516297483497836521
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-091-base-pr-000.dot
* REASONING
* DIS # E2: 2,9 => CTR => E2: 5,7,8
* DIS # A2: 2,9 => CTR => A2: 5,8
* PRF # I1: 8,9 => SOL
* PRF # C1: 2 => SOL
* DIS # B6: 8,9 => CTR => B6: 2,5
* DIS # B7: 8,9 => CTR => B7: 2,5
* PRF # H8: 8,9 => SOL
* DIS # H8: 2 => CTR => H8: 8,9
* DIS # B6: 8,9 => CTR => B6: 2,5
* PRF # B7: 2,9 => SOL
* DIS # A8: 2,9 => CTR => A8: 5,8
* DIS # B6: 2,9 => CTR => B6: 5,8
* PRF # E8: 2,9 => SOL
* DIS # A8: 2,9 => CTR => A8: 5,8
* DIS # H8: 2,9 => CTR => H8: 8
* PRF # H8: 8 => SOL
* PRF # H8: 8,9 => SOL
* DIS # H8: 2 => CTR => H8: 8,9
* DIS # B7: 8,9 => CTR => B7: 2,5
* PRF # I1: 8,9 => SOL
* DIS # H8: 2,9 => CTR => H8: 8
* PRF # H8: 8 => SOL
* CNT  22 HDP CHAINS /  51 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B4,B9,D2,D8,E5,F5,G1,G6,H4,H9,I7)
* 74.613.5..61...34..3.4..1761.35426.76743..215...761.343..1.476..16...4.34.78365.1
* PAIR D2: 2,9 BLK 2
E2: 2,9,5,7,8                            # reduction candidate for 2,9
E2: 2,9 => CTR
* 748613952561..7348.3.458176183542697674389215...7618343..124769216975483497836521
E3: 2,9,5,8                              # reduction candidate for 2,9
E3: 2,9                                  # 13 pairs
* RESTART
* PAIR D2: 2,9 BLK 2
E3: 2,9,5,8                              # reduction candidate for 2,9
E3: 5,8                                  # 14 pairs
E3: 2,9                                  # 13 pairs
* PAIR D2: 2,9 ROW 2
A2: 2,9,5,8                              # reduction candidate for 2,9
A2: 2,9 => CTR
* 748613952.61...348.3.4..1761835426976743..215...7618343..1.4769.16...483497836521
I2: 2,9,8                                # reduction candidate for 2,9
I2: 2,9                                  # 14 pairs
* RESTART
* PAIR D2: 2,9 ROW 2
I2: 2,9,8                                # reduction candidate for 2,9
I2: 8 => CTR
* 748613952561279348.3.485176183542697674398215...7618343..1.4769216957483497836521
* PAIR RESTART
* PAIR D2: 2,9 BLK 2
E3: 2,9,5,8                              # reduction candidate for 2,9
E3: 5,8 => CTR
* 74.613.5..612..349.3.4.91761.35426.7674398215...7619343..1.4768.16...4.34.78365.1
* PAIR G1: 8,9 BLK 3
I1: 8,9,2                                # reduction candidate for 8,9
I1: 8,9 => SOLVED
* 742613958861975342935428176183542697674389215259761834328154769516297483497836521
* DURATION: 0:00:11.643642  START: 05:54:53.091733  END: 05:55:04.735375 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-091-base-pr-001.dot
* REASONING
* DIS # E2: 2,9 => CTR => E2: 5,7,8
* DIS E2: 5,7,8 # A2: 2,9 => CTR => A2: 5,8
* DIS E2: 5,7,8 + A2: 5,8 # I2: 8 => CTR => I2: 2,9
* DIS E2: 5,7,8 + A2: 5,8 + I2: 2,9 # E3: 5,8 => CTR => E3: 2,9
* PRF E2: 5,7,8 + A2: 5,8 + I2: 2,9 + E3: 2,9 # I1: 8,9 => SOL
* STA E2: 5,7,8 + A2: 5,8 + I2: 2,9 + E3: 2,9 + I1: 8,9
* CNT   5 HDP CHAINS /  11 HYP OPENED

Header Info

Top 500 Minimum 17 091

solution: 742613958861975342935428176183542697674389215259761834328154769516297483497836521
info: 1566     FNBTWXY  S8.f     45336

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

Solution

position: 742613958861975342935428176183542697674389215259761834328154769516297483497836521 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 # E2: 2,9 => CTR => E2: 5,7,8
* INC # E2: 5,7,8 => UNS
* INC # E3: 2,9 => UNS
* DIS # A2: 2,9 => CTR => A2: 5,8
* INC # A2: 5,8 => UNS
* INC # I2: 2,9 => UNS
* PRF # I1: 8,9 => SOL
* INC # I1: 2 => UNS
* INC # I2: 8,9 => UNS
* INC # C1: 8,9 => UNS
* PRF # C1: 2 => SOL
* INC # A6: 8,9 => UNS
* DIS # B6: 8,9 => CTR => B6: 2,5
* INC # B6: 2,5 => UNS
* INC # C6: 8,9 => UNS
* DIS # B7: 8,9 => CTR => B7: 2,5
* INC # B7: 2,5 => UNS
* INC # E2: 8,9 => UNS
* INC # E3: 8,9 => UNS
* INC # F2: 8,9 => UNS
* INC # F3: 8,9 => UNS
* PRF # H8: 8,9 => SOL
* DIS # H8: 2 => CTR => H8: 8,9
* INC # A6: 8,9 => UNS
* DIS # B6: 8,9 => CTR => B6: 2,5
* INC # B6: 2,5 => UNS
* INC # C6: 8,9 => UNS
* PRF # B7: 2,9 => SOL
* INC # B7: 5,8 => UNS
* INC # C7: 2,9 => UNS
* DIS # A8: 2,9 => CTR => A8: 5,8
* INC # A8: 5,8 => UNS
* DIS # B6: 2,9 => CTR => B6: 5,8
* INC # B6: 5,8 => UNS
* INC # E7: 2,9 => UNS
* PRF # E8: 2,9 => SOL
* INC # E8: 5,7 => UNS
* DIS # A8: 2,9 => CTR => A8: 5,8
* INC # A8: 5,8 => UNS
* DIS # H8: 2,9 => CTR => H8: 8
* PRF # H8: 8 => SOL
* PRF # H8: 8,9 => SOL
* DIS # H8: 2 => CTR => H8: 8,9
* DIS # B7: 8,9 => CTR => B7: 2,5
* INC # B7: 2,5 => UNS
* INC # C7: 8,9 => UNS
* PRF # I1: 8,9 => SOL
* INC # I1: 2 => UNS
* INC # I2: 8,9 => UNS
* DIS # H8: 2,9 => CTR => H8: 8
* PRF # H8: 8 => SOL
* CNT  51 HDP CHAINS /  51 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # E2: 2,9 => CTR => E2: 5,7,8
* INC E2: 5,7,8 # E3: 2,9 => UNS
* INC E2: 5,7,8 # E3: 2,9 => UNS
* INC E2: 5,7,8 # E3: 5,8 => UNS
* DIS E2: 5,7,8 # A2: 2,9 => CTR => A2: 5,8
* INC E2: 5,7,8 + A2: 5,8 # I2: 2,9 => UNS
* INC E2: 5,7,8 + A2: 5,8 # I2: 2,9 => UNS
* DIS E2: 5,7,8 + A2: 5,8 # I2: 8 => CTR => I2: 2,9
* INC E2: 5,7,8 + A2: 5,8 + I2: 2,9 # E3: 2,9 => UNS
* DIS E2: 5,7,8 + A2: 5,8 + I2: 2,9 # E3: 5,8 => CTR => E3: 2,9
* PRF E2: 5,7,8 + A2: 5,8 + I2: 2,9 + E3: 2,9 # I1: 8,9 => SOL
* STA E2: 5,7,8 + A2: 5,8 + I2: 2,9 + E3: 2,9 + I1: 8,9
* CNT  11 HDP CHAINS /  11 HYP OPENED