Analysis of xx-top500-212-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .21.3.......6...5.........96..5...........2......4.......72.1..4......3.58....... initial

Autosolve

position: .21.35......6...52...2...196..5.2...1.....2..2...4.5.....72.1.5412.5..3.587....2. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # E2: 7,8 => CTR => E2: 1,9
* DIS # F2: 7,8 => CTR => F2: 1,9
* DIS # F3: 7,8 => CTR => F3: 4
* PRF # F3: 4 => SOL
* PRF # A3: 7,8 => SOL
* DIS # A3: 3 => CTR => A3: 7,8
* DIS # G3: 7,8 => CTR => G3: 3,4
* DIS # E5: 7,8 => CTR => E5: 6,9
* DIS # A2: 3,9 => CTR => A2: 7,8
* DIS # F3: 7 => CTR => F3: 4,8
* DIS # F8: 8,9 => CTR => F8: 6
* PRF # D1: 8,9 => SOL
* DIS # D1: 4 => CTR => D1: 8,9
* DIS # D5: 8,9 => CTR => D5: 3
* DIS # D6: 8,9 => CTR => D6: 1,3
* DIS # G9: 4,6 => CTR => G9: 9
* DIS # F9: 4,6 => CTR => F9: 1,3,9
* CNT  17 HDP CHAINS /  38 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: 7,8 => CTR => E2: 1,9
* DIS E2: 1,9 # F2: 7,8 => CTR => F2: 1,9
* PRF E2: 1,9 + F2: 1,9 => SOL
* STA E2: 1,9 + F2: 1,9
* CNT   3 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

.21.3.......6...5.........96..5...........2......4.......72.1..4......3.58....... initial
.21.35......6...52...2...196..5.2...1.....2..2...4.5.....72.1.5412.5..3.587....2. autosolve
921835674734691852856274319673582491145369287298147563369728145412956738587413926 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (8)
B3: 5,6
C3: 5,6
E3: 7,8
A7: 3,9
F7: 4,8
D8: 8,9
H7: 4,8
I9: 4,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E2,F2: 1.. / E2 = 1  =>  0 pairs (X) / F2 = 1  =>  8 pairs (_)
I4,I6: 1.. / I4 = 1  => 10 pairs (_) / I6 = 1  =>  0 pairs (X)
E4,I4: 1.. / E4 = 1  =>  0 pairs (X) / I4 = 1  => 10 pairs (_)
D6,D9: 1.. / D6 = 1  => 10 pairs (_) / D9 = 1  =>  0 pairs (X)
G2,G3: 3.. / G2 = 3  =>  0 pairs (X) / G3 = 3  =>  0 pairs (_)
D9,F9: 3.. / D9 = 3  =>  0 pairs (X) / F9 = 3  =>  8 pairs (_)
A3,G3: 3.. / A3 = 3  =>  0 pairs (X) / G3 = 3  =>  0 pairs (_)
B2,C2: 4.. / B2 = 4  =>  9 pairs (_) / C2 = 4  =>  9 pairs (_)
D1,F3: 4.. / D1 = 4  =>  0 pairs (X) / F3 = 4  =>  0 pairs (_)
F3,G3: 4.. / F3 = 4  =>  0 pairs (*) / G3 = 4  =>  0 pairs (X)
F7,H7: 4.. / F7 = 4  =>  0 pairs (X) / H7 = 4  =>  0 pairs (_)
D1,D9: 4.. / D1 = 4  =>  0 pairs (X) / D9 = 4  =>  0 pairs (_)
B3,C3: 5.. / B3 = 5  =>  7 pairs (_) / C3 = 5  =>  7 pairs (_)
B5,C5: 5.. / B5 = 5  =>  7 pairs (_) / C5 = 5  =>  7 pairs (_)
B3,B5: 5.. / B3 = 5  =>  7 pairs (_) / B5 = 5  =>  7 pairs (_)
C3,C5: 5.. / C3 = 5  =>  7 pairs (_) / C5 = 5  =>  7 pairs (_)
B3,C3: 6.. / B3 = 6  =>  7 pairs (_) / C3 = 6  =>  7 pairs (_)
B7,C7: 6.. / B7 = 6  =>  7 pairs (_) / C7 = 6  =>  7 pairs (_)
B3,B7: 6.. / B3 = 6  =>  7 pairs (_) / B7 = 6  =>  7 pairs (_)
C3,C7: 6.. / C3 = 6  =>  7 pairs (_) / C7 = 6  =>  7 pairs (_)
E5,E9: 6.. / E5 = 6  =>  9 pairs (_) / E9 = 6  =>  0 pairs (X)
G8,I8: 7.. / G8 = 7  => 13 pairs (_) / I8 = 7  =>  8 pairs (_)
F7,H7: 8.. / F7 = 8  =>  0 pairs (*) / H7 = 8  =>  0 pairs (X)
G8,G9: 9.. / G8 = 9  =>  0 pairs (X) / G9 = 9  =>  9 pairs (_)
A1,D1: 9.. / A1 = 9  =>  0 pairs (*) / D1 = 9  =>  0 pairs (X)
* DURATION: 0:00:37.650363  START: 10:04:25.647893  END: 10:05:03.298256 2017-05-04
* CP COUNT: (25)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A7,B3,C3,D8,E3,F7,H7,I9)
* .21.35......6...52...2...196..5.2...1.....2..2...4.5.....72.1.5412.5..3.587....2.
* PAIR E3: 7,8 BLK 2
E2: 7,8,1,9                              # reduction candidate for 7,8
E2: 7,8 => CTR
* .21935......6.1.52...2.4.196..5.2...1.....2..2...4.5.....7281.5412.5..3.587....2.
E2: 1,9                                  #  9 pairs
F2: 7,8,1,9                              # reduction candidate for 7,8
F2: 7,8 => CTR
* .21935......61..52...2.4.196..5.2..11.....2..2...4.5.....7281.5412.5..3.587....2.
F2: 1,9                                  #  9 pairs
F3: 7,8,4                                # reduction candidate for 7,8
F3: 7,8 => CTR
* 921435......6..3523..2..4196..5.2...1.....2..2...4.5.....72.1.5412.5..3.587....2.
F3: 4 => SOLVED
* 921835674734691852856274319673582491145369287298147563369728145412956738587413926
* PAIR E3: 7,8 ROW 3
A3: 7,8,3                                # reduction candidate for 7,8
A3: 7,8 => SOLVED
* 921835674734691852856274319673582491145369287298147563369728145412956738587413926
A3: 3 => CTR
* .21935......6..3523..2.4.196..5.2...1.....2..2...4.5..9..7281.5412.5..3.587....2.
G3: 7,8,3,4                              # reduction candidate for 7,8
G3: 7,8 => CTR
* .21.35......6..3523..2.4.196..5.2...1.....2..2...4.5..9..728145412956.3.587413926
G3: 3,4                                  #  9 pairs
* PAIR E3: 7,8 COL E
E4: 7,8,1,9                              # reduction candidate for 7,8
E4: 7,8                                  # 13 pairs
E5: 7,8,6,9                              # reduction candidate for 7,8
E5: 7,8 => CTR
* 921435......6..3523..2..4196..5.2...1.....2..2...4.5.....724185412.5..3.587.6.924
E5: 6,9                                  #  9 pairs
* PAIR A7: 3,9 BLK 7
B7: 3,9,6                                # reduction candidate for 3,9
B7: 3,9                                  #  7 pairs
C7: 3,9,6                                # reduction candidate for 3,9
C7: 3,9                                  #  7 pairs
* PAIR A7: 3,9 COL A
A2: 3,9,7,8                              # reduction candidate for 3,9
A2: 3,9 => CTR
* .21935......6...52...2.43196..5.2...1.....2..2...4.5.....7281.5412.5..3.587....2.
A2: 7,8                                  #  9 pairs
* PAIR F7: 4,8 COL F
F3: 4,8,7                                # reduction candidate for 4,8
F3: 7 => CTR
* 921435...7..6..352...2.74196..5.2...1.....2..2...4.5.....72.1.5412.5..3.587....2.
F3: 4,8                                  # 10 pairs
* PAIR D8: 8,9 BLK 8
F8: 8,9,6                                # reduction candidate for 8,9
F8: 8,9 => CTR
* 921435......6..3523..2..4196..5.2...1.....2..2...4.5.....724185412.5..3.587...924
F8: 6                                    # 10 pairs
* PAIR D8: 8,9 ROW 8
G8: 8,9,6,7                              # reduction candidate for 8,9
G8: 8,9                                  # 10 pairs
G8: 6,7                                  # 10 pairs
* PAIR D8: 8,9 COL D
D1: 8,9,4                                # reduction candidate for 8,9
D1: 8,9 => SOLVED
* 921835674734691852856274319673582491145369287298147563369728145412956738587413926
D1: 4 => CTR
* 921435......6...52...2..4196..5.2...1.....2..2...4.5..3..72.1.5412.5..3.587....2.
D5: 8,9,3                                # reduction candidate for 8,9
D5: 8,9 => CTR
* 921435......6...52...2..4196..5.2...1.....2..2...4.5..3..72.1.5412.5..3.587....2.
D5: 3                                    # 10 pairs
D6: 8,9,1,3                              # reduction candidate for 8,9
D6: 8,9 => CTR
* 921435......6..3523..2..4196..5.2...1..3..2..2...4.5.....724185412.5..3.5871.3.24
D6: 1,3                                  #  9 pairs
* PAIR H7: 4,8 COL H
H1: 4,8,6,7                              # reduction candidate for 4,8
H1: 4,8                                  # 11 pairs
H4: 4,8,7,9                              # reduction candidate for 4,8
H4: 4,8                                  # 10 pairs
H5: 4,8,6,7,9                            # reduction candidate for 4,8
H5: 4,8                                  # 11 pairs
* PAIR I9: 4,6 BLK 9
G9: 4,6,9                                # reduction candidate for 4,6
G9: 4,6 => CTR
* 921435......6..3523..2..4196..5.2...1...6.2..2...4.5.....724185412856937587...624
G9: 9                                    #  9 pairs
* PAIR I9: 4,6 ROW 9
F9: 4,6,1,3,9                            # reduction candidate for 4,6
F9: 4,6 => CTR
* 921435......6913523..2..4196..5.2..11...6.2..2..14.5.....72.1.5412.5..3.58731.92.
F9: 1,3,9                                #  8 pairs
* PAIR I9: 4,6 COL I
I1: 4,6,7,8                              # reduction candidate for 4,6
I1: 4,6                                  # 10 pairs
I5: 4,6,3,7,8                            # reduction candidate for 4,6
I5: 4,6                                  # 13 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-212-base-pr-000.dot
* REASONING
* DIS # E2: 7,8 => CTR => E2: 1,9
* DIS # F2: 7,8 => CTR => F2: 1,9
* DIS # F3: 7,8 => CTR => F3: 4
* PRF # F3: 4 => SOL
* PRF # A3: 7,8 => SOL
* DIS # A3: 3 => CTR => A3: 7,8
* DIS # G3: 7,8 => CTR => G3: 3,4
* DIS # E5: 7,8 => CTR => E5: 6,9
* DIS # A2: 3,9 => CTR => A2: 7,8
* DIS # F3: 7 => CTR => F3: 4,8
* DIS # F8: 8,9 => CTR => F8: 6
* PRF # D1: 8,9 => SOL
* DIS # D1: 4 => CTR => D1: 8,9
* DIS # D5: 8,9 => CTR => D5: 3
* DIS # D6: 8,9 => CTR => D6: 1,3
* DIS # G9: 4,6 => CTR => G9: 9
* DIS # F9: 4,6 => CTR => F9: 1,3,9
* CNT  17 HDP CHAINS /  38 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A7,B3,C3,D8,E3,F7,H7,I9)
* .21.35......6...52...2...196..5.2...1.....2..2...4.5.....72.1.5412.5..3.587....2.
* PAIR E3: 7,8 BLK 2
E2: 7,8,1,9                              # reduction candidate for 7,8
E2: 7,8 => CTR
* .21935......6.1.52...2.4.196..5.2...1.....2..2...4.5.....7281.5412.5..3.587....2.
F2: 7,8,1,9                              # reduction candidate for 7,8
F2: 7,8 => CTR
* .21935......61..52...2.4.196..5.2..11.....2..2...4.5.....7281.5412.5..3.587....2.
F2: 1,9 => SOLVED
* 921835674734691852856274319673582491145369287298147563369728145412956738587413926
* DURATION: 0:00:02.611457  START: 10:05:34.413393  END: 10:05:37.024850 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-212-base-pr-001.dot
* REASONING
* DIS # E2: 7,8 => CTR => E2: 1,9
* DIS E2: 1,9 # F2: 7,8 => CTR => F2: 1,9
* PRF E2: 1,9 + F2: 1,9 => SOL
* STA E2: 1,9 + F2: 1,9
* CNT   3 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 212

solution: 921835674734691852856274319673582491145369287298147563369728145412956738587413926
info: 1945     FNBHWXY  S8.f     17063

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

Solution

position: 921835674734691852856274319673582491145369287298147563369728145412956738587413926 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: 7,8 => CTR => E2: 1,9
* INC # E2: 1,9 => UNS
* DIS # F2: 7,8 => CTR => F2: 1,9
* INC # F2: 1,9 => UNS
* DIS # F3: 7,8 => CTR => F3: 4
* PRF # F3: 4 => SOL
* PRF # A3: 7,8 => SOL
* DIS # A3: 3 => CTR => A3: 7,8
* DIS # G3: 7,8 => CTR => G3: 3,4
* INC # G3: 3,4 => UNS
* INC # E4: 7,8 => UNS
* DIS # E5: 7,8 => CTR => E5: 6,9
* INC # E5: 6,9 => UNS
* INC # B7: 3,9 => UNS
* INC # C7: 3,9 => UNS
* DIS # A2: 3,9 => CTR => A2: 7,8
* INC # A2: 7,8 => UNS
* INC # F3: 4,8 => UNS
* DIS # F3: 7 => CTR => F3: 4,8
* DIS # F8: 8,9 => CTR => F8: 6
* INC # F8: 6 => UNS
* INC # G8: 8,9 => UNS
* INC # G8: 6,7 => UNS
* PRF # D1: 8,9 => SOL
* DIS # D1: 4 => CTR => D1: 8,9
* DIS # D5: 8,9 => CTR => D5: 3
* INC # D5: 3 => UNS
* DIS # D6: 8,9 => CTR => D6: 1,3
* INC # D6: 1,3 => UNS
* INC # H1: 4,8 => UNS
* INC # H4: 4,8 => UNS
* INC # H5: 4,8 => UNS
* DIS # G9: 4,6 => CTR => G9: 9
* INC # G9: 9 => UNS
* DIS # F9: 4,6 => CTR => F9: 1,3,9
* INC # F9: 1,3,9 => UNS
* INC # I1: 4,6 => UNS
* INC # I5: 4,6 => UNS
* CNT  38 HDP CHAINS /  38 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # E2: 7,8 => CTR => E2: 1,9
* DIS E2: 1,9 # F2: 7,8 => CTR => F2: 1,9
* PRF E2: 1,9 + F2: 1,9 => SOL
* STA E2: 1,9 + F2: 1,9
* CNT   3 HDP CHAINS /   2 HYP OPENED