Analysis of xx-top500-020-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .13...5.....9...4..............13..862...........5....4......637..2...........1.. initial

Autosolve

position: .13...5..5..981342...3.5.1.9..6132586258...31138.52...4521...637.123...53..5..12. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # E1: 4,7 => SOL
* DIS # F1: 4,7 => CTR => F1: 6
* DIS # I1: 6,7 => CTR => I1: 9
* PRF # G3: 6,7 => SOL
* PRF # E3: 2 => SOL
* PRF # I6: 6,7 => SOL
* DIS # F5: 4,7 => CTR => F5: 9
* DIS # G6: 4,7 => CTR => G6: 6,9
* DIS # I6: 4,7 => CTR => I6: 6,9
* PRF # I6: 6,9 => SOL
* DIS # G6: 4,7 => CTR => G6: 6,9
* DIS # I6: 4,7 => CTR => I6: 6,9
* PRF # I6: 6,9 => SOL
* DIS # F5: 4,7 => CTR => F5: 9
* PRF # G6: 7,9 => SOL
* DIS # I6: 7,9 => CTR => I6: 4,6
* PRF # H1: 8 => SOL
* DIS # B9: 6,9 => CTR => B9: 8
* DIS # F9: 6,9 => CTR => F9: 4,7,8
* DIS # F7: 7,9 => CTR => F7: 8
* DIS # E9: 7,9 => CTR => E9: 4,6
* DIS # G7: 8 => CTR => G7: 7,9
* PRF # E5: 7,9 => SOL
* DIS # E5: 4 => CTR => E5: 7,9
* DIS # G7: 8,9 => CTR => G7: 7
* PRF # G7: 7 => SOL
* PRF # G8: 8,9 => SOL
* DIS # G8: 4 => CTR => G8: 8,9
* DIS # B8: 8,9 => CTR => B8: 6
* DIS # F8: 8,9 => CTR => F8: 4,6
* PRF # H1: 8,9 => SOL
* DIS # H1: 7 => CTR => H1: 8,9
* CNT  32 HDP CHAINS /  57 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 # E1: 4,7 => SOL
* STA E1: 4,7
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

.13...5.....9...4..............13..862...........5....4......637..2...........1.. initial
.13...5..5..981342...3.5.1.9..6132586258...31138.52...4521...637.123...53..5..12. autosolve
213746589576981342894325617947613258625879431138452976452198763761234895389567124 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (16)
A1: 2,8
B2: 6,7
C2: 6,7
A3: 2,8
B3: 4,9
C3: 4,9
D1: 4,7
I3: 6,7
B4: 4,7
C4: 4,7
D6: 4,7
G5: 4,7
H6: 7,9
C9: 6,9
E7: 7,9
H8: 8,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A1,A3: 2.. / A1 = 2  =>  0 pairs (*) / A3 = 2  =>  0 pairs (X)
E1,E3: 2.. / E1 = 2  => 19 pairs (_) / E3 = 2  =>  0 pairs (*)
A1,E1: 2.. / A1 = 2  =>  0 pairs (*) / E1 = 2  =>  0 pairs (X)
A3,E3: 2.. / A3 = 2  => 19 pairs (_) / E3 = 2  =>  0 pairs (*)
B3,C3: 4.. / B3 = 4  =>  0 pairs (X) / C3 = 4  => 12 pairs (_)
B4,C4: 4.. / B4 = 4  => 12 pairs (_) / C4 = 4  =>  0 pairs (X)
G8,I9: 4.. / G8 = 4  =>  0 pairs (X) / I9 = 4  =>  0 pairs (_)
F8,G8: 4.. / F8 = 4  =>  0 pairs (*) / G8 = 4  =>  0 pairs (X)
B3,B4: 4.. / B3 = 4  =>  0 pairs (X) / B4 = 4  => 12 pairs (_)
C3,C4: 4.. / C3 = 4  => 12 pairs (_) / C4 = 4  =>  0 pairs (X)
D1,D6: 4.. / D1 = 4  =>  0 pairs (X) / D6 = 4  =>  0 pairs (_)
I6,I9: 4.. / I6 = 4  =>  0 pairs (X) / I9 = 4  =>  0 pairs (_)
B2,C2: 6.. / B2 = 6  =>  0 pairs (X) / C2 = 6  => 12 pairs (_)
G6,I6: 6.. / G6 = 6  => 19 pairs (_) / I6 = 6  =>  0 pairs (*)
B8,F8: 6.. / B8 = 6  => 10 pairs (_) / F8 = 6  =>  0 pairs (X)
C2,C9: 6.. / C2 = 6  => 12 pairs (_) / C9 = 6  =>  0 pairs (X)
G3,G6: 6.. / G3 = 6  =>  0 pairs (*) / G6 = 6  =>  0 pairs (X)
B2,C2: 7.. / B2 = 7  => 12 pairs (_) / C2 = 7  =>  0 pairs (X)
B4,C4: 7.. / B4 = 7  =>  0 pairs (X) / C4 = 7  => 12 pairs (_)
G7,I9: 7.. / G7 = 7  =>  0 pairs (*) / I9 = 7  =>  0 pairs (X)
B2,B4: 7.. / B2 = 7  => 12 pairs (_) / B4 = 7  =>  0 pairs (X)
C2,C4: 7.. / C2 = 7  =>  0 pairs (X) / C4 = 7  => 12 pairs (_)
D1,D6: 7.. / D1 = 7  =>  0 pairs (*) / D6 = 7  =>  0 pairs (X)
H1,H6: 7.. / H1 = 7  =>  0 pairs (X) / H6 = 7  =>  0 pairs (_)
A1,A3: 8.. / A1 = 8  => 19 pairs (_) / A3 = 8  =>  0 pairs (*)
H1,G3: 8.. / H1 = 8  =>  0 pairs (*) / G3 = 8  =>  0 pairs (X)
B8,B9: 8.. / B8 = 8  =>  0 pairs (X) / B9 = 8  => 17 pairs (_)
A1,H1: 8.. / A1 = 8  => 19 pairs (_) / H1 = 8  =>  0 pairs (*)
A3,G3: 8.. / A3 = 8  =>  0 pairs (*) / G3 = 8  =>  0 pairs (X)
F7,G7: 8.. / F7 = 8  => 18 pairs (_) / G7 = 8  =>  0 pairs (X)
B9,F9: 8.. / B9 = 8  => 17 pairs (_) / F9 = 8  =>  0 pairs (X)
H1,H8: 8.. / H1 = 8  =>  0 pairs (*) / H8 = 8  =>  0 pairs (X)
B3,C3: 9.. / B3 = 9  => 12 pairs (_) / C3 = 9  =>  0 pairs (X)
H1,I1: 9.. / H1 = 9  =>  0 pairs (X) / I1 = 9  => 19 pairs (_)
E5,F5: 9.. / E5 = 9  =>  0 pairs (X) / F5 = 9  => 18 pairs (_)
C3,C9: 9.. / C3 = 9  =>  0 pairs (X) / C9 = 9  => 12 pairs (_)
* DURATION: 0:01:06.126649  START: 03:15:28.554362  END: 03:16:34.681011 2017-05-04
* CP COUNT: (36)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A3,B2,B3,B4,C2,C3,C4,C9,D1,D6,E7,G5,H6,H8,I3)
* .13...5..5..981342...3.5.1.9..6132586258...31138.52...4521...637.123...53..5..12.
* PAIR D1: 4,7 BLK 2
E1: 4,7,2,6                              # reduction candidate for 4,7
E1: 4,7 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
E1: 2,6                                  # 17 pairs
F1: 4,7,6                                # reduction candidate for 4,7
F1: 4,7 => CTR
* .137.45..5..981342...3.5.1.9..6132586258..431138452.7.4521...637.123...53..54.12.
F1: 6                                    # 14 pairs
* PAIR I3: 6,7 BLK 3
I1: 6,7,9                                # reduction candidate for 6,7
I1: 6,7 => CTR
* 8137245965.698134229436581794761325862584..31138.526794521.87637.123.9853895..124
I1: 9                                    # 19 pairs
G3: 6,7,8                                # reduction candidate for 6,7
G3: 6,7 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
G3: 8                                    # 19 pairs
* PAIR I3: 6,7 ROW 3
E3: 6,7,2                                # reduction candidate for 6,7
E3: 2 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
E3: 6,7                                  # 19 pairs
* PAIR I3: 6,7 COL I
I6: 6,7,4,9                              # reduction candidate for 6,7
I6: 6,7 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
I6: 4,9                                  # 20 pairs
* PAIR D6: 4,7 BLK 5
E5: 4,7,9                                # reduction candidate for 4,7
E5: 4,7                                  # 18 pairs
F5: 4,7,9                                # reduction candidate for 4,7
F5: 4,7 => CTR
* .13...5..5..981342...3.57169..61325862589743113845267945217..637.123...53..5..127
F5: 9                                    # 18 pairs
* PAIR D6: 4,7 ROW 6
G6: 4,7,6,9                              # reduction candidate for 4,7
G6: 4,7 => CTR
* .13...5..5..981342...3.56179..6132586258...31138.52.7.4521...637.123...53..5..12.
G6: 6,9                                  # 17 pairs
I6: 4,7,6,9                              # reduction candidate for 4,7
I6: 4,7 => CTR
* 813.2.5795..9813422..3758169..6132586258...311387526944521987637.123..8538.5..12.
I6: 6,9 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
* PAIR G5: 4,7 BLK 6
G6: 4,7,6,9                              # reduction candidate for 4,7
G6: 4,7 => CTR
* .13...5..5..981342...3.56179..6132586258...31138.52.7.4521...637.123...53..5..12.
G6: 6,9                                  # 17 pairs
I6: 4,7,6,9                              # reduction candidate for 4,7
I6: 4,7 => CTR
* 813.2.5795..9813422..3758169..6132586258...311387526944521987637.123..8538.5..12.
I6: 6,9 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
* PAIR G5: 4,7 ROW 5
E5: 4,7,9                                # reduction candidate for 4,7
E5: 4,7                                  # 18 pairs
F5: 4,7,9                                # reduction candidate for 4,7
F5: 4,7 => CTR
* .13...5..5..981342...3.57169..61325862589743113845267945217..637.123...53..5..127
F5: 9                                    # 18 pairs
* PAIR H6: 7,9 BLK 6
G6: 7,9,4,6                              # reduction candidate for 7,9
G6: 7,9 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
G6: 4,6                                  # 19 pairs
I6: 7,9,4,6                              # reduction candidate for 7,9
I6: 7,9 => CTR
* 8137..5..5..981342...3.5.1.9..6132586258..4311384526..4521..7637.12349853895..124
I6: 4,6                                  # 17 pairs
* PAIR H6: 7,9 COL H
H1: 7,9,8                                # reduction candidate for 7,9
H1: 8 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
H1: 7,9                                  # 19 pairs
* PAIR C9: 6,9 BLK 7
B8: 6,9,8                                # reduction candidate for 6,9
B8: 6,9                                  # 17 pairs
B9: 6,9,8                                # reduction candidate for 6,9
B9: 6,9 => CTR
* .13...5..5..981342...3.5.1.9..6132586258...31138.52...4521...637812364953..5.8127
B9: 8                                    # 17 pairs
* PAIR C9: 6,9 ROW 9
E9: 6,9,4,7                              # reduction candidate for 6,9
E9: 6,9                                  # 22 pairs
F9: 6,9,4,7,8                            # reduction candidate for 6,9
F9: 6,9 => CTR
* .13...5..5..981342...3.5.1.9..6132586258..431138452.7.4521...637.1234..538.576124
F9: 4,7,8                                # 16 pairs
* PAIR E7: 7,9 BLK 8
F7: 7,9,8                                # reduction candidate for 7,9
F7: 7,9 => CTR
* .13...5895..9813428..3257169..6132586258..431138.52...4521..8637.123..953..5..127
F7: 8                                    # 18 pairs
E9: 7,9,4,6                              # reduction candidate for 7,9
E9: 7,9 => CTR
* .13..75..5..981342...3.5.1.9..6132586258.9.31138752.9.4521.8.637.123..853..5..12.
E9: 4,6                                  # 17 pairs
F9: 7,9,4,6,8                            # reduction candidate for 7,9
F9: 7,9                                  # 21 pairs
* PAIR E7: 7,9 ROW 7
G7: 7,9,8                                # reduction candidate for 7,9
G7: 8 => CTR
* .13...5895..9813428..3257169..6132586258..431138.52...4521..8637.123..953..5..127
G7: 7,9                                  # 18 pairs
* PAIR E7: 7,9 COL E
E5: 7,9,4                                # reduction candidate for 7,9
E5: 7,9 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
E5: 4 => CTR
* 81342.5795..9813422..3758169..61325862584973113875269445219..637.123..8538.5..127
* PAIR H8: 8,9 BLK 9
G7: 8,9,7                                # reduction candidate for 8,9
G7: 8,9 => CTR
* 8134265795..9813422..375.169..6132586258..7311387526944521..9637.123.48538.5..127
G7: 7 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
G8: 8,9,4                                # reduction candidate for 8,9
G8: 8,9 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
G8: 4 => CTR
* 81342.5795..9813422..375.1.9..6132586258..731138752.944521..9637.123.48538.5..127
* PAIR H8: 8,9 ROW 8
B8: 8,9,6                                # reduction candidate for 8,9
B8: 8,9 => CTR
* 8134275..5..981342...3.5.1.9..6132586258..731138752.944521..9637912364853865..127
B8: 6                                    # 10 pairs
F8: 8,9,4,6                              # reduction candidate for 8,9
F8: 8,9 => CTR
* 813426579576981342294375.169476132586258..7311387526944521..9637612394853895..127
F8: 4,6                                  # 17 pairs
* PAIR H8: 8,9 COL H
H1: 8,9,7                                # reduction candidate for 8,9
H1: 8,9 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
H1: 7 => CTR
* 813.2.5795..9813422..3758169..6132586258...311387526944521987637.123...53..5..12.
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-020-base-pr-000.dot
* REASONING
* PRF # E1: 4,7 => SOL
* DIS # F1: 4,7 => CTR => F1: 6
* DIS # I1: 6,7 => CTR => I1: 9
* PRF # G3: 6,7 => SOL
* PRF # E3: 2 => SOL
* PRF # I6: 6,7 => SOL
* DIS # F5: 4,7 => CTR => F5: 9
* DIS # G6: 4,7 => CTR => G6: 6,9
* DIS # I6: 4,7 => CTR => I6: 6,9
* PRF # I6: 6,9 => SOL
* DIS # G6: 4,7 => CTR => G6: 6,9
* DIS # I6: 4,7 => CTR => I6: 6,9
* PRF # I6: 6,9 => SOL
* DIS # F5: 4,7 => CTR => F5: 9
* PRF # G6: 7,9 => SOL
* DIS # I6: 7,9 => CTR => I6: 4,6
* PRF # H1: 8 => SOL
* DIS # B9: 6,9 => CTR => B9: 8
* DIS # F9: 6,9 => CTR => F9: 4,7,8
* DIS # F7: 7,9 => CTR => F7: 8
* DIS # E9: 7,9 => CTR => E9: 4,6
* DIS # G7: 8 => CTR => G7: 7,9
* PRF # E5: 7,9 => SOL
* DIS # E5: 4 => CTR => E5: 7,9
* DIS # G7: 8,9 => CTR => G7: 7
* PRF # G7: 7 => SOL
* PRF # G8: 8,9 => SOL
* DIS # G8: 4 => CTR => G8: 8,9
* DIS # B8: 8,9 => CTR => B8: 6
* DIS # F8: 8,9 => CTR => F8: 4,6
* PRF # H1: 8,9 => SOL
* DIS # H1: 7 => CTR => H1: 8,9
* CNT  32 HDP CHAINS /  57 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A3,B2,B3,B4,C2,C3,C4,C9,D1,D6,E7,G5,H6,H8,I3)
* .13...5..5..981342...3.5.1.9..6132586258...31138.52...4521...637.123...53..5..12.
* PAIR D1: 4,7 BLK 2
E1: 4,7,2,6                              # reduction candidate for 4,7
E1: 4,7 => SOLVED
* 213746589576981342894325617947613258625879431138452976452198763761234895389567124
* DURATION: 0:00:02.461539  START: 03:17:33.584426  END: 03:17:36.045965 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-020-base-pr-001.dot
* REASONING
* PRF # E1: 4,7 => SOL
* STA E1: 4,7
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 020

solution: 213746589576981342894325617947613258625879431138452976452198763761234895389567124
info: 1312     FNBWXY   S8.f     15843

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

Solution

position: 213746589576981342894325617947613258625879431138452976452198763761234895389567124 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:

* PRF # E1: 4,7 => SOL
* INC # E1: 2,6 => UNS
* DIS # F1: 4,7 => CTR => F1: 6
* INC # F1: 6 => UNS
* DIS # I1: 6,7 => CTR => I1: 9
* INC # I1: 9 => UNS
* PRF # G3: 6,7 => SOL
* INC # G3: 8 => UNS
* INC # E3: 6,7 => UNS
* PRF # E3: 2 => SOL
* PRF # I6: 6,7 => SOL
* INC # I6: 4,9 => UNS
* INC # E5: 4,7 => UNS
* DIS # F5: 4,7 => CTR => F5: 9
* INC # F5: 9 => UNS
* DIS # G6: 4,7 => CTR => G6: 6,9
* INC # G6: 6,9 => UNS
* DIS # I6: 4,7 => CTR => I6: 6,9
* PRF # I6: 6,9 => SOL
* DIS # G6: 4,7 => CTR => G6: 6,9
* INC # G6: 6,9 => UNS
* DIS # I6: 4,7 => CTR => I6: 6,9
* PRF # I6: 6,9 => SOL
* INC # E5: 4,7 => UNS
* DIS # F5: 4,7 => CTR => F5: 9
* INC # F5: 9 => UNS
* PRF # G6: 7,9 => SOL
* INC # G6: 4,6 => UNS
* DIS # I6: 7,9 => CTR => I6: 4,6
* INC # I6: 4,6 => UNS
* INC # H1: 7,9 => UNS
* PRF # H1: 8 => SOL
* INC # B8: 6,9 => UNS
* DIS # B9: 6,9 => CTR => B9: 8
* INC # B9: 8 => UNS
* INC # E9: 6,9 => UNS
* DIS # F9: 6,9 => CTR => F9: 4,7,8
* INC # F9: 4,7,8 => UNS
* DIS # F7: 7,9 => CTR => F7: 8
* INC # F7: 8 => UNS
* DIS # E9: 7,9 => CTR => E9: 4,6
* INC # E9: 4,6 => UNS
* INC # F9: 7,9 => UNS
* INC # G7: 7,9 => UNS
* DIS # G7: 8 => CTR => G7: 7,9
* PRF # E5: 7,9 => SOL
* DIS # E5: 4 => CTR => E5: 7,9
* DIS # G7: 8,9 => CTR => G7: 7
* PRF # G7: 7 => SOL
* PRF # G8: 8,9 => SOL
* DIS # G8: 4 => CTR => G8: 8,9
* DIS # B8: 8,9 => CTR => B8: 6
* INC # B8: 6 => UNS
* DIS # F8: 8,9 => CTR => F8: 4,6
* INC # F8: 4,6 => UNS
* PRF # H1: 8,9 => SOL
* DIS # H1: 7 => CTR => H1: 8,9
* CNT  57 HDP CHAINS /  57 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # E1: 4,7 => SOL
* STA E1: 4,7
* CNT   1 HDP CHAINS /   1 HYP OPENED