Analysis of xx-top95-081-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 15.3......7..4.2....4.72.....8.........9..1.8.1..8.79......38...........6....7423 initial

Autosolve

position: 1523.8....7..4.2....4.72.....87........9..1.8.1..8.79......38...........6....7423 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # F2: 6,9 => CTR => F2: 1,5
* PRF # F2: 1,5 => SOL
* DIS # I2: 6,9 => CTR => I2: 1,5
* DIS # A8: 8,9 => CTR => A8: 2,3,4,5,7
* DIS # B8: 8,9 => CTR => B8: 2,3,4
* DIS # B3: 8,9 => CTR => B3: 3,6
* CNT   6 HDP CHAINS /  16 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 # F2: 6,9 => CTR => F2: 1,5
* PRF F2: 1,5 => SOL
* STA F2: 1,5
* CNT   2 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

15.3......7..4.2....4.72.....8.........9..1.8.1..8.79......38...........6....7423 initial
1523.8....7..4.2....4.72.....87........9..1.8.1..8.79......38...........6....7423 autosolve
152398647973641285864572931598714362247936158316285794725463819431829576689157423 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (5)
E1: 6,9
G1: 6,9
H1: 4,7
I1: 4,7
B9: 8,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E4,F4: 1.. / E4 = 1  =>  9 pairs (_) / F4 = 1  =>  6 pairs (_)
I4,I6: 2.. / I4 = 2  =>  5 pairs (_) / I6 = 2  =>  0 pairs (X)
A6,C6: 3.. / A6 = 3  =>  0 pairs (*) / C6 = 3  =>  0 pairs (X)
E4,E5: 3.. / E4 = 3  =>  8 pairs (_) / E5 = 3  =>  5 pairs (_)
E5,H5: 3.. / E5 = 3  =>  5 pairs (_) / H5 = 3  =>  8 pairs (_)
B3,B8: 3.. / B3 = 3  =>  0 pairs (X) / B8 = 3  =>  5 pairs (_)
G3,G4: 3.. / G3 = 3  =>  7 pairs (_) / G4 = 3  =>  7 pairs (_)
H1,I1: 4.. / H1 = 4  =>  5 pairs (_) / I1 = 4  =>  3 pairs (_)
C2,B3: 6.. / C2 = 6  =>  0 pairs (X) / B3 = 6  =>  0 pairs (_)
E1,G1: 6.. / E1 = 6  =>  0 pairs (X) / G1 = 6  =>  0 pairs (_)
H1,I1: 7.. / H1 = 7  =>  3 pairs (_) / I1 = 7  =>  5 pairs (_)
A5,C5: 7.. / A5 = 7  =>  6 pairs (_) / C5 = 7  =>  5 pairs (_)
H2,H3: 8.. / H2 = 8  =>  7 pairs (_) / H3 = 8  =>  6 pairs (_)
D8,D9: 8.. / D8 = 8  =>  0 pairs (*) / D9 = 8  =>  0 pairs (X)
A2,H2: 8.. / A2 = 8  =>  6 pairs (_) / H2 = 8  =>  7 pairs (_)
B9,D9: 8.. / B9 = 8  =>  0 pairs (*) / D9 = 8  =>  0 pairs (X)
E1,F2: 9.. / E1 = 9  =>  0 pairs (*) / F2 = 9  =>  0 pairs (X)
A4,B4: 9.. / A4 = 9  =>  0 pairs (X) / B4 = 9  =>  0 pairs (_)
E1,G1: 9.. / E1 = 9  =>  0 pairs (*) / G1 = 9  =>  0 pairs (X)
F2,F8: 9.. / F2 = 9  =>  0 pairs (X) / F8 = 9  =>  0 pairs (_)
* DURATION: 0:00:27.948327  START: 00:49:16.836695  END: 00:49:44.785022 2017-05-04
* CP COUNT: (20)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B9,E1,G1,H1,I1)
* 1523.8....7..4.2....4.72.....87........9..1.8.1..8.79......38...........6....7423
* PAIR E1: 6,9 BLK 2
F2: 6,9,1,5                              # reduction candidate for 6,9
F2: 6,9 => CTR
* 1523.8....79.462...64.72...9.87........9..1.8.1..8.79......38...........69.8.7423
F2: 1,5 => SOLVED
* 152398647973641285864572931598714362247936158316285794725463819431829576689157423
* PAIR E1: 6,9 COL E
E7: 6,9,1,2,5                            # reduction candidate for 6,9
E7: 6,9                                  #  8 pairs
E8: 6,9,1,2,5                            # reduction candidate for 6,9
E8: 6,9                                  #  9 pairs
* PAIR G1: 6,9 BLK 3
I2: 6,9,1,5                              # reduction candidate for 6,9
I2: 6,9 => CTR
* 1523986...7..4.2.9..4.72.....87........9..1.8.1..8.79...9..38.....8.95..68...7423
I2: 1,5                                  #  6 pairs
G3: 6,9,3,5                              # reduction candidate for 6,9
G3: 6,9                                  # 11 pairs
I3: 6,9,1,5                              # reduction candidate for 6,9
I3: 6,9                                  #  8 pairs
* PAIR G1: 6,9 COL G
G8: 6,9,5                                # reduction candidate for 6,9
G8: 6,9                                  #  8 pairs
G8: 5                                    #  6 pairs
* PAIR B9: 8,9 BLK 7
A8: 8,9,2,3,4,5,7                        # reduction candidate for 8,9
A8: 8,9 => CTR
* 1523.8....79.4.2...64.72.....87........9..1.8.1..8.79......38...3...9...6....7423
A8: 2,3,4,5,7                            #  5 pairs
B8: 8,9,2,3,4                            # reduction candidate for 8,9
B8: 8,9 => CTR
* 1523.8...876.4.23.934.72.8..987..3...6.93.1.8.1..8.79......38...........6....7423
B8: 2,3,4                                #  5 pairs
* PAIR B9: 8,9 COL B
B3: 8,9,3,6                              # reduction candidate for 8,9
B3: 8,9 => CTR
* 1523986...76.4.2.9.94672...9.87........9..1.8.13.8.79...9..38...3.8.95..68...7423
B3: 3,6                                  #  6 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top95-081-base-pr-000.dot
* REASONING
* DIS # F2: 6,9 => CTR => F2: 1,5
* PRF # F2: 1,5 => SOL
* DIS # I2: 6,9 => CTR => I2: 1,5
* DIS # A8: 8,9 => CTR => A8: 2,3,4,5,7
* DIS # B8: 8,9 => CTR => B8: 2,3,4
* DIS # B3: 8,9 => CTR => B3: 3,6
* CNT   6 HDP CHAINS /  16 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (B9,E1,G1,H1,I1)
* 1523.8....7..4.2....4.72.....87........9..1.8.1..8.79......38...........6....7423
* PAIR E1: 6,9 BLK 2
F2: 6,9,1,5                              # reduction candidate for 6,9
F2: 6,9 => CTR
* 1523.8....79.462...64.72...9.87........9..1.8.1..8.79......38...........69.8.7423
F2: 1,5 => SOLVED
* 152398647973641285864572931598714362247936158316285794725463819431829576689157423
* DURATION: 0:00:03.261960  START: 00:49:56.330509  END: 00:49:59.592469 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top95-081-base-pr-001.dot
* REASONING
* DIS # F2: 6,9 => CTR => F2: 1,5
* PRF F2: 1,5 => SOL
* STA F2: 1,5
* CNT   2 HDP CHAINS /   1 HYP OPENED

Header Info

Top 95 Sudokus 081
[sudoku:top95] “95 Hard Puzzles”, http://magictour.free.fr/top95, or http://norvig.com/top95.txt

Solution

position: 152398647973641285864572931598714362247936158316285794725463819431829576689157423 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 # F2: 6,9 => CTR => F2: 1,5
* PRF # F2: 1,5 => SOL
* INC # E7: 6,9 => UNS
* INC # E8: 6,9 => UNS
* DIS # I2: 6,9 => CTR => I2: 1,5
* INC # I2: 1,5 => UNS
* INC # G3: 6,9 => UNS
* INC # I3: 6,9 => UNS
* INC # G8: 6,9 => UNS
* INC # G8: 5 => UNS
* DIS # A8: 8,9 => CTR => A8: 2,3,4,5,7
* INC # A8: 2,3,4,5,7 => UNS
* DIS # B8: 8,9 => CTR => B8: 2,3,4
* INC # B8: 2,3,4 => UNS
* DIS # B3: 8,9 => CTR => B3: 3,6
* INC # B3: 3,6 => UNS
* CNT  16 HDP CHAINS /  16 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # F2: 6,9 => CTR => F2: 1,5
* PRF F2: 1,5 => SOL
* STA F2: 1,5
* CNT   2 HDP CHAINS /   1 HYP OPENED