Analysis of xx-top500-358-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....57.1..1....9......2.......4..63.5..8.....2........8...9...5.3.6.............. initial

Autosolve

position: 38.95721..123..95795712....7984156325..8.279.2..7.95..87.29...5.3567..29.295...7. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # F2: 8 => CTR => F2: 4,6
* DIS # A9: 1 => CTR => A9: 4,6
* DIS # F2: 4,8 => CTR => F2: 6
* PRF # F2: 6 => SOL
* DIS # F2: 8 => CTR => F2: 4,6
* DIS # H3: 4,6 => CTR => H3: 8
* PRF # H3: 8 => SOL
* PRF # I3: 4,6 => SOL
* DIS # H3: 4,6 => CTR => H3: 8
* PRF # H3: 8 => SOL
* PRF # I3: 4,6 => SOL
* DIS # I9: 4,6 => CTR => I9: 3,8
* PRF # I9: 3,8 => SOL
* DIS # I6: 1,4 => CTR => I6: 8
* PRF # I6: 8 => SOL
* DIS # I6: 1 => CTR => I6: 4,8
* PRF # H3: 4,8 => SOL
* DIS # H3: 6 => CTR => H3: 4,8
* DIS # A9: 1 => CTR => A9: 4,6
* DIS # A9: 1,4 => CTR => A9: 6
* PRF # A9: 6 => SOL
* DIS # F9: 4,8 => CTR => F9: 1,3
* DIS # F9: 4,8 => CTR => F9: 1,3
* DIS # I9: 4,8 => CTR => I9: 3,6
* DIS # I9: 4,6 => CTR => I9: 3,8
* PRF # I9: 3,8 => SOL
* DIS # H3: 4,6 => CTR => H3: 8
* PRF # H3: 8 => SOL
* CNT  28 HDP CHAINS /  44 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: 8 => CTR => F2: 4,6
* DIS F2: 4,6 # H3: 4,6 => CTR => H3: 8
* PRF F2: 4,6 + H3: 8 => SOL
* STA F2: 4,6 + H3: 8
* CNT   3 HDP CHAINS /   3 HYP OPENED

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

Details

Positions

....57.1..1....9......2.......4..63.5..8.....2........8...9...5.3.6.............. initial
38.95721..123..95795712....7984156325..8.279.2..7.95..87.29...5.3567..29.295...7. autosolve
386957214412386957957124386798415632543862791261739548874293165135678429629541873 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (19)
C1: 4,6
A2: 4,6
E2: 4,8
F3: 4,6
I1: 4,6
B5: 4,6
C5: 1,3
B6: 4,6
C6: 1,3
E5: 3,6
E6: 3,6
I5: 1,4
H6: 4,8
C7: 4,6
A8: 1,4
F7: 1,3
E9: 4,8
G7: 1,3
H7: 4,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
C5,C6: 1.. / C5 = 1  =>  0 pairs (X) / C6 = 1  => 13 pairs (_)
I5,I6: 1.. / I5 = 1  => 13 pairs (_) / I6 = 1  =>  0 pairs (X)
A8,A9: 1.. / A8 = 1  => 22 pairs (_) / A9 = 1  =>  0 pairs (X)
C5,I5: 1.. / C5 = 1  =>  0 pairs (X) / I5 = 1  => 13 pairs (_)
C6,I6: 1.. / C6 = 1  => 13 pairs (_) / I6 = 1  =>  0 pairs (X)
F7,G7: 1.. / F7 = 1  => 19 pairs (_) / G7 = 1  => 18 pairs (_)
G3,I3: 3.. / G3 = 3  =>  0 pairs (*) / I3 = 3  =>  0 pairs (X)
C5,C6: 3.. / C5 = 3  => 13 pairs (_) / C6 = 3  =>  0 pairs (X)
E5,E6: 3.. / E5 = 3  =>  0 pairs (X) / E6 = 3  => 13 pairs (_)
F7,F9: 3.. / F7 = 3  => 18 pairs (_) / F9 = 3  => 19 pairs (_)
C5,E5: 3.. / C5 = 3  => 13 pairs (_) / E5 = 3  =>  0 pairs (X)
C6,E6: 3.. / C6 = 3  =>  0 pairs (X) / E6 = 3  => 13 pairs (_)
F7,G7: 3.. / F7 = 3  => 18 pairs (_) / G7 = 3  => 19 pairs (_)
I3,I9: 3.. / I3 = 3  => 20 pairs (_) / I9 = 3  =>  0 pairs (*)
C1,A2: 4.. / C1 = 4  =>  0 pairs (X) / A2 = 4  =>  0 pairs (_)
B5,B6: 4.. / B5 = 4  => 13 pairs (_) / B6 = 4  =>  0 pairs (X)
C1,I1: 4.. / C1 = 4  =>  0 pairs (X) / I1 = 4  =>  0 pairs (_)
B5,I5: 4.. / B5 = 4  => 13 pairs (_) / I5 = 4  =>  0 pairs (X)
C7,H7: 4.. / C7 = 4  =>  0 pairs (*) / H7 = 4  =>  0 pairs (X)
C1,C7: 4.. / C1 = 4  =>  0 pairs (X) / C7 = 4  =>  0 pairs (_)
E2,E9: 4.. / E2 = 4  =>  0 pairs (X) / E9 = 4  => 20 pairs (_)
C1,A2: 6.. / C1 = 6  =>  0 pairs (*) / A2 = 6  =>  0 pairs (X)
F2,F3: 6.. / F2 = 6  =>  0 pairs (*) / F3 = 6  =>  0 pairs (X)
B5,B6: 6.. / B5 = 6  =>  0 pairs (X) / B6 = 6  => 13 pairs (_)
E5,E6: 6.. / E5 = 6  => 13 pairs (_) / E6 = 6  =>  0 pairs (X)
C7,A9: 6.. / C7 = 6  =>  0 pairs (X) / A9 = 6  =>  0 pairs (_)
H7,I9: 6.. / H7 = 6  =>  0 pairs (*) / I9 = 6  =>  0 pairs (X)
C1,I1: 6.. / C1 = 6  =>  0 pairs (*) / I1 = 6  =>  0 pairs (X)
A2,F2: 6.. / A2 = 6  =>  0 pairs (X) / F2 = 6  =>  0 pairs (_)
B5,E5: 6.. / B5 = 6  =>  0 pairs (X) / E5 = 6  => 13 pairs (_)
B6,E6: 6.. / B6 = 6  => 13 pairs (_) / E6 = 6  =>  0 pairs (X)
C7,H7: 6.. / C7 = 6  =>  0 pairs (X) / H7 = 6  =>  0 pairs (_)
A9,I9: 6.. / A9 = 6  =>  0 pairs (*) / I9 = 6  =>  0 pairs (X)
A2,A9: 6.. / A2 = 6  =>  0 pairs (X) / A9 = 6  =>  0 pairs (_)
C1,C7: 6.. / C1 = 6  =>  0 pairs (*) / C7 = 6  =>  0 pairs (X)
H3,H7: 6.. / H3 = 6  =>  0 pairs (X) / H7 = 6  =>  0 pairs (_)
E2,F2: 8.. / E2 = 8  => 20 pairs (_) / F2 = 8  =>  0 pairs (X)
H6,I6: 8.. / H6 = 8  =>  0 pairs (X) / I6 = 8  =>  0 pairs (_)
F8,G8: 8.. / F8 = 8  => 21 pairs (_) / G8 = 8  => 21 pairs (_)
E2,E9: 8.. / E2 = 8  => 20 pairs (_) / E9 = 8  =>  0 pairs (X)
H3,H6: 8.. / H3 = 8  =>  0 pairs (*) / H6 = 8  =>  0 pairs (X)
* DURATION: 0:01:25.429824  START: 14:59:17.813789  END: 15:00:43.243613 2017-05-04
* CP COUNT: (41)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A8,B5,B6,C1,C5,C6,C7,E2,E5,E6,E9,F3,F7,G7,H6,H7,I1,I5)
* 38.95721..123..95795712....7984156325..8.279.2..7.95..87.29...5.3567..29.295...7.
* PAIR A2: 4,6 ROW 2
F2: 4,6,8                                # reduction candidate for 4,6
F2: 8 => CTR
* 38.95721.612348957957126...7984156325..8.279.2..7.95..87629..45.3567.829.2958..76
F2: 4,6                                  # 20 pairs
* PAIR A2: 4,6 COL A
A9: 4,6,1                                # reduction candidate for 4,6
A9: 1 => CTR
* 38.95721.6123..957957126...7984156325..8.279.2..7.95..87629..4543567..291295...76
A9: 4,6                                  # 22 pairs
* PAIR E2: 4,8 BLK 2
F2: 4,8,6                                # reduction candidate for 4,8
F2: 4,8 => CTR
* 38.95721.6123..957957126...7984156325..8.279.2..7.95..87629..45.3567..29.295...76
F2: 6 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
* PAIR F3: 4,6 BLK 2
F2: 4,6,8                                # reduction candidate for 4,6
F2: 8 => CTR
* 38.95721.612348957957126...7984156325..8.279.2..7.95..87629..45.3567.829.2958..76
F2: 4,6                                  # 20 pairs
* PAIR F3: 4,6 ROW 3
H3: 4,6,8                                # reduction candidate for 4,6
H3: 4,6 => CTR
* 3849572166123..957957126.4.7984156325..8.279.2..7.958.87.29...5.3567..29.295...7.
H3: 8 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
I3: 4,6,3,8                              # reduction candidate for 4,6
I3: 4,6 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
I3: 3,8                                  # 20 pairs
* PAIR I1: 4,6 BLK 3
H3: 4,6,8                                # reduction candidate for 4,6
H3: 4,6 => CTR
* 3849572166123..957957126.4.7984156325..8.279.2..7.958.87.29...5.3567..29.295...7.
H3: 8 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
I3: 4,6,3,8                              # reduction candidate for 4,6
I3: 4,6 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
I3: 3,8                                  # 20 pairs
* PAIR I1: 4,6 COL I
I9: 4,6,3,8                              # reduction candidate for 4,6
I9: 4,6 => CTR
* 38.95721..123..95795712..837984156325..8.27912.173954887429..6513567..296295...74
I9: 3,8 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
* PAIR I5: 1,4 BLK 6
I6: 1,4,8                                # reduction candidate for 1,4
I6: 1,4 => CTR
* 3849572166123..957957126.4.7984156325..8.279.2..7.958.87.29...5.3567..29.295...7.
I6: 8 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
* PAIR H6: 4,8 BLK 6
I6: 4,8,1                                # reduction candidate for 4,8
I6: 1 => CTR
* 3849572166123..957957126.4.7984156325.183279424376958187.29...5.3567..29.295...7.
I6: 4,8                                  # 13 pairs
* PAIR H6: 4,8 COL H
H3: 4,8,6                                # reduction candidate for 4,8
H3: 4,8 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
H3: 6 => CTR
* 38.95721..123..95795712..6.7984156325..8.279.2..7.958.87629..45.3567..29.295...76
* PAIR C7: 4,6 BLK 7
A9: 4,6,1                                # reduction candidate for 4,6
A9: 1 => CTR
* 38.95721.6123..957957126...7984156325..8.279.2..7.95..87629..4543567..291295...76
A9: 4,6                                  # 22 pairs
* PAIR A8: 1,4 BLK 7
A9: 1,4,6                                # reduction candidate for 1,4
A9: 1,4 => CTR
* 38.95721.6123..957957126...7984156325..8.279.2..7.95..87629..45.3567..29.295...76
A9: 6 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
* PAIR A8: 1,4 ROW 8
F8: 1,4,8                                # reduction candidate for 1,4
F8: 1,4                                  # 21 pairs
G8: 1,4,8                                # reduction candidate for 1,4
G8: 1,4                                  # 21 pairs
* PAIR F7: 1,3 BLK 8
F9: 1,3,4,8                              # reduction candidate for 1,3
F9: 4,8 => CTR
* 3869572144123..95795712....7984156325..8.279.2..7.95..87.2931.5.356718291295...76
F9: 1,3                                  # 21 pairs
* PAIR E9: 4,8 BLK 8
F8: 4,8,1                                # reduction candidate for 4,8
F8: 4,8                                  # 21 pairs
F9: 4,8,1,3                              # reduction candidate for 4,8
F9: 4,8 => CTR
* 3869572144123..95795712....7984156325..8.279.2..7.95..87.2931.5.356718291295...76
F9: 1,3                                  # 21 pairs
* PAIR E9: 4,8 ROW 9
G9: 4,8,1,3                              # reduction candidate for 4,8
G9: 4,8                                  # 25 pairs
I9: 4,8,3,6                              # reduction candidate for 4,8
I9: 4,8 => CTR
* 38695721441238.95795712...37984156325..8.279.2..7.95..87.29..65.3567..296295...7.
I9: 3,6                                  # 21 pairs
* PAIR G7: 1,3 BLK 9
G9: 1,3,4,8                              # reduction candidate for 1,3
G9: 4,8                                  # 25 pairs
G9: 1,3                                  # 22 pairs
* PAIR H7: 4,6 BLK 9
I9: 4,6,3,8                              # reduction candidate for 4,6
I9: 4,6 => CTR
* 38.95721..123..95795712..837984156325..8.27912.173954887429..6513567..296295...74
I9: 3,8 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
* PAIR H7: 4,6 COL H
H3: 4,6,8                                # reduction candidate for 4,6
H3: 4,6 => CTR
* 3849572166123..957957126.4.7984156325..8.279.2..7.958.87.29...5.3567..29.295...7.
H3: 8 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-358-base-pr-000.dot
* REASONING
* DIS # F2: 8 => CTR => F2: 4,6
* DIS # A9: 1 => CTR => A9: 4,6
* DIS # F2: 4,8 => CTR => F2: 6
* PRF # F2: 6 => SOL
* DIS # F2: 8 => CTR => F2: 4,6
* DIS # H3: 4,6 => CTR => H3: 8
* PRF # H3: 8 => SOL
* PRF # I3: 4,6 => SOL
* DIS # H3: 4,6 => CTR => H3: 8
* PRF # H3: 8 => SOL
* PRF # I3: 4,6 => SOL
* DIS # I9: 4,6 => CTR => I9: 3,8
* PRF # I9: 3,8 => SOL
* DIS # I6: 1,4 => CTR => I6: 8
* PRF # I6: 8 => SOL
* DIS # I6: 1 => CTR => I6: 4,8
* PRF # H3: 4,8 => SOL
* DIS # H3: 6 => CTR => H3: 4,8
* DIS # A9: 1 => CTR => A9: 4,6
* DIS # A9: 1,4 => CTR => A9: 6
* PRF # A9: 6 => SOL
* DIS # F9: 4,8 => CTR => F9: 1,3
* DIS # F9: 4,8 => CTR => F9: 1,3
* DIS # I9: 4,8 => CTR => I9: 3,6
* DIS # I9: 4,6 => CTR => I9: 3,8
* PRF # I9: 3,8 => SOL
* DIS # H3: 4,6 => CTR => H3: 8
* PRF # H3: 8 => SOL
* CNT  28 HDP CHAINS /  44 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,A8,B5,B6,C1,C5,C6,C7,E2,E5,E6,E9,F3,F7,G7,H6,H7,I1,I5)
* 38.95721..123..95795712....7984156325..8.279.2..7.95..87.29...5.3567..29.295...7.
* PAIR A2: 4,6 ROW 2
F2: 4,6,8                                # reduction candidate for 4,6
F2: 8 => CTR
* 38.95721.612348957957126...7984156325..8.279.2..7.95..87629..45.3567.829.2958..76
* PAIR RESTART
* PAIR F3: 4,6 ROW 3
H3: 4,6,8                                # reduction candidate for 4,6
H3: 4,6 => CTR
* 384957216612384957957126.4.7984156325..8.279.2..7.958.87.29...5.3567..29.2954..7.
H3: 8 => SOLVED
* 386957214412386957957124386798415632543862791261739548874293165135678429629541873
* DURATION: 0:00:04.283444  START: 15:01:36.688043  END: 15:01:40.971487 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-358-base-pr-001.dot
* REASONING
* DIS # F2: 8 => CTR => F2: 4,6
* DIS F2: 4,6 # H3: 4,6 => CTR => H3: 8
* PRF F2: 4,6 + H3: 8 => SOL
* STA F2: 4,6 + H3: 8
* CNT   3 HDP CHAINS /   3 HYP OPENED

Header Info

Top 500 Minimum 17 358

solution: 386957214412386957957124386798415632543862791261739548874293165135678429629541873
info: 4897     FNBTWX   S8.f     5063

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

Solution

position: 386957214412386957957124386798415632543862791261739548874293165135678429629541873 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 # F2: 4,6 => UNS
* DIS # F2: 8 => CTR => F2: 4,6
* INC # A9: 4,6 => UNS
* DIS # A9: 1 => CTR => A9: 4,6
* DIS # F2: 4,8 => CTR => F2: 6
* PRF # F2: 6 => SOL
* INC # F2: 4,6 => UNS
* DIS # F2: 8 => CTR => F2: 4,6
* DIS # H3: 4,6 => CTR => H3: 8
* PRF # H3: 8 => SOL
* PRF # I3: 4,6 => SOL
* INC # I3: 3,8 => UNS
* DIS # H3: 4,6 => CTR => H3: 8
* PRF # H3: 8 => SOL
* PRF # I3: 4,6 => SOL
* INC # I3: 3,8 => UNS
* DIS # I9: 4,6 => CTR => I9: 3,8
* PRF # I9: 3,8 => SOL
* DIS # I6: 1,4 => CTR => I6: 8
* PRF # I6: 8 => SOL
* INC # I6: 4,8 => UNS
* DIS # I6: 1 => CTR => I6: 4,8
* PRF # H3: 4,8 => SOL
* DIS # H3: 6 => CTR => H3: 4,8
* INC # A9: 4,6 => UNS
* DIS # A9: 1 => CTR => A9: 4,6
* DIS # A9: 1,4 => CTR => A9: 6
* PRF # A9: 6 => SOL
* INC # F8: 1,4 => UNS
* INC # G8: 1,4 => UNS
* INC # F9: 1,3 => UNS
* DIS # F9: 4,8 => CTR => F9: 1,3
* INC # F8: 4,8 => UNS
* DIS # F9: 4,8 => CTR => F9: 1,3
* INC # F9: 1,3 => UNS
* INC # G9: 4,8 => UNS
* DIS # I9: 4,8 => CTR => I9: 3,6
* INC # I9: 3,6 => UNS
* INC # G9: 1,3 => UNS
* INC # G9: 4,8 => UNS
* DIS # I9: 4,6 => CTR => I9: 3,8
* PRF # I9: 3,8 => SOL
* DIS # H3: 4,6 => CTR => H3: 8
* PRF # H3: 8 => SOL
* CNT  44 HDP CHAINS /  44 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # F2: 4,6 => UNS
* DIS # F2: 8 => CTR => F2: 4,6
* DIS F2: 4,6 # H3: 4,6 => CTR => H3: 8
* PRF F2: 4,6 + H3: 8 => SOL
* STA F2: 4,6 + H3: 8
* CNT   4 HDP CHAINS /   3 HYP OPENED