Analysis of xx-top500-445-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 1....5.9.....1...4..............615...49......2........8.47....5.....8.....2..... initial

Autosolve

position: 14...529...5.12..42...94.15..9.46152.54921....215.74.9.8647.5215.216.84.41.2589.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # D1: 3,8 => CTR => D1: 6,7
* DIS # I1: 3,8 => CTR => I1: 6,7
* PRF # A4: 8 => SOL
* DIS # B2: 3,7 => CTR => B2: 6,9
* DIS # B3: 3,7 => CTR => B3: 6
* PRF # A4: 3,8 => SOL
* DIS # D1: 3,8 => CTR => D1: 6,7
* PRF # B8: 3,9 => SOL
* DIS # B8: 7 => CTR => B8: 3,9
* PRF # A2: 7 => SOL
* DIS # B8: 9 => CTR => B8: 3,7
* PRF # C3: 3,7 => SOL
* PRF # B8: 3,9 => SOL
* DIS # B8: 7 => CTR => B8: 3,9
* DIS # B8: 9 => CTR => B8: 3,7
* DIS # I5: 3,7 => CTR => I5: 6,8
* CNT  16 HDP CHAINS /  42 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 # D1: 3,8 => CTR => D1: 6,7
* DIS D1: 6,7 # I1: 3,8 => CTR => I1: 6,7
* DIS D1: 6,7 + I1: 6,7 # D3: 6,7 => CTR => D3: 3,8
* DIS D1: 6,7 + I1: 6,7 + D3: 3,8 # A4: 3,7 => CTR => A4: 8
* PRF D1: 6,7 + I1: 6,7 + D3: 3,8 + A4: 8 => SOL
* STA D1: 6,7 + I1: 6,7 + D3: 3,8 + A4: 8
* CNT   5 HDP CHAINS /   8 HYP OPENED

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

Details

Positions

1....5.9.....1...4..............615...49......2........8.47....5.....8.....2..... initial
14...529...5.12..42...94.15..9.46152.54921....215.74.9.8647.5215.216.84.41.2589.. autosolve
148735296795612384263894715879346152354921678621587439986473521532169847417258963 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (9)
E1: 3,8
B4: 3,7
D4: 3,8
E6: 3,8
A7: 3,9
C9: 3,7
F7: 3,9
F8: 3,9
I8: 3,7

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
D4,E6: 3.. / D4 = 3  =>  0 pairs (*) / E6 = 3  =>  0 pairs (X)
F7,F8: 3.. / F7 = 3  =>  9 pairs (_) / F8 = 3  =>  0 pairs (X)
A7,F7: 3.. / A7 = 3  =>  0 pairs (X) / F7 = 3  =>  9 pairs (_)
E1,E6: 3.. / E1 = 3  =>  0 pairs (*) / E6 = 3  =>  0 pairs (X)
B2,B3: 6.. / B2 = 6  =>  0 pairs (X) / B3 = 6  => 10 pairs (_)
A5,A6: 6.. / A5 = 6  => 12 pairs (_) / A6 = 6  => 11 pairs (_)
H9,I9: 6.. / H9 = 6  => 14 pairs (_) / I9 = 6  => 10 pairs (_)
D1,I1: 6.. / D1 = 6  =>  9 pairs (_) / I1 = 6  =>  0 pairs (*)
A6,H6: 6.. / A6 = 6  => 11 pairs (_) / H6 = 6  => 12 pairs (_)
A4,B4: 7.. / A4 = 7  => 15 pairs (_) / B4 = 7  =>  0 pairs (*)
B8,C9: 7.. / B8 = 7  =>  0 pairs (X) / C9 = 7  =>  0 pairs (_)
B8,I8: 7.. / B8 = 7  =>  0 pairs (X) / I8 = 7  =>  0 pairs (_)
A2,A4: 7.. / A2 = 7  =>  0 pairs (*) / A4 = 7  =>  0 pairs (X)
C1,C3: 8.. / C1 = 8  =>  0 pairs (*) / C3 = 8  =>  0 pairs (X)
I1,H2: 8.. / I1 = 8  =>  0 pairs (X) / H2 = 8  => 11 pairs (_)
D4,E6: 8.. / D4 = 8  => 14 pairs (_) / E6 = 8  =>  0 pairs (*)
D2,H2: 8.. / D2 = 8  =>  0 pairs (X) / H2 = 8  => 11 pairs (_)
C3,D3: 8.. / C3 = 8  => 10 pairs (_) / D3 = 8  =>  0 pairs (*)
A4,D4: 8.. / A4 = 8  =>  0 pairs (*) / D4 = 8  =>  0 pairs (X)
E1,E6: 8.. / E1 = 8  => 14 pairs (_) / E6 = 8  =>  0 pairs (*)
I1,I5: 8.. / I1 = 8  =>  0 pairs (X) / I5 = 8  => 11 pairs (_)
A2,B2: 9.. / A2 = 9  =>  0 pairs (X) / B2 = 9  =>  9 pairs (_)
A7,B8: 9.. / A7 = 9  =>  9 pairs (_) / B8 = 9  =>  0 pairs (X)
F7,F8: 9.. / F7 = 9  =>  0 pairs (X) / F8 = 9  =>  9 pairs (_)
A7,F7: 9.. / A7 = 9  =>  9 pairs (_) / F7 = 9  =>  0 pairs (X)
B8,F8: 9.. / B8 = 9  =>  0 pairs (X) / F8 = 9  =>  9 pairs (_)
A2,A7: 9.. / A2 = 9  =>  0 pairs (X) / A7 = 9  =>  9 pairs (_)
B2,B8: 9.. / B2 = 9  =>  9 pairs (_) / B8 = 9  =>  0 pairs (X)
* DURATION: 0:00:49.969684  START: 17:57:10.624238  END: 17:58:00.593922 2017-05-04
* CP COUNT: (28)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A7,B4,C9,D4,E1,E6,F7,F8,I8)
* 14...529...5.12..42...94.15..9.46152.54921....215.74.9.8647.5215.216.84.41.2589..
* PAIR E1: 3,8 BLK 2
D1: 3,8,6,7                              # reduction candidate for 3,8
D1: 3,8 => CTR
* 147835296..5.12.842.8.94.15..9.46152.549216.8621587439.8647.5215.216.84.41.25896.
D1: 6,7                                  # 10 pairs
D2: 3,8,6,7                              # reduction candidate for 3,8
D2: 3,8                                  # 13 pairs
D3: 3,8,6,7                              # reduction candidate for 3,8
D3: 3,8                                  # 14 pairs
* PAIR E1: 3,8 ROW 1
C1: 3,8,7                                # reduction candidate for 3,8
C1: 3,8                                  # 16 pairs
I1: 3,8,6,7                              # reduction candidate for 3,8
I1: 3,8 => CTR
* 1476.529...5.12..42.8.94.15739846152.54921....215374.9.8647.5215721698434132589..
I1: 6,7                                  # 14 pairs
* PAIR B4: 3,7 BLK 4
A4: 3,7,8                                # reduction candidate for 3,7
A4: 8 => SOLVED
* 148735296795612384263894715879346152354921678621587439986473521532169847417258963
A4: 3,7                                  # 14 pairs
* PAIR B4: 3,7 COL B
B2: 3,7,6,9                              # reduction candidate for 3,7
B2: 3,7 => CTR
* 14.785296975612384268394715739846152.549216...215374.93864795215921638474172589..
B2: 6,9                                  # 10 pairs
B3: 3,7,6                                # reduction candidate for 3,7
B3: 3,7 => CTR
* 14.7.5296965.12.8427.694315739846152.5492167..215.74.9.8647.5215921638474172589..
B3: 6                                    # 10 pairs
B8: 3,7,9                                # reduction candidate for 3,7
B8: 3,7                                  #  9 pairs
* PAIR D4: 3,8 ROW 4
A4: 3,8,7                                # reduction candidate for 3,8
A4: 3,8 => SOLVED
* 148735296795612384263894715879346152354921678621587439986473521532169847417258963
A4: 7                                    # 15 pairs
* PAIR D4: 3,8 COL D
D1: 3,8,6,7                              # reduction candidate for 3,8
D1: 3,8 => CTR
* 147835296..5.12.842.8.94.15..9.46152.549216.8621587439.8647.5215.216.84.41.25896.
D1: 6,7                                  # 10 pairs
D2: 3,8,6,7                              # reduction candidate for 3,8
D2: 3,8                                  # 13 pairs
D3: 3,8,6,7                              # reduction candidate for 3,8
D3: 3,8                                  # 14 pairs
* PAIR E6: 3,8 ROW 6
A6: 3,8,6                                # reduction candidate for 3,8
A6: 3,8                                  # 12 pairs
H6: 3,8,6                                # reduction candidate for 3,8
H6: 3,8                                  # 11 pairs
* PAIR A7: 3,9 BLK 7
B8: 3,9,7                                # reduction candidate for 3,9
B8: 3,9 => SOLVED
* 148735296795612384263894715879346152354921678621587439986473521532169847417258963
B8: 7 => CTR
* 14.385296395612784268794315739846152.549216...215374.99864735215721698434132589..
* PAIR A7: 3,9 COL A
A2: 3,9,7                                # reduction candidate for 3,9
A2: 7 => SOLVED
* 148735296795612384263894715879346152354921678621587439986473521532169847417258963
A2: 3,9                                  # 15 pairs
* PAIR C9: 3,7 BLK 7
B8: 3,7,9                                # reduction candidate for 3,7
B8: 9 => CTR
* 14.7.52969.5.12.842...94.15739846152.5492167..215.74.9.8647.5215921638474172589..
B8: 3,7                                  #  9 pairs
* PAIR C9: 3,7 ROW 9
H9: 3,7,6                                # reduction candidate for 3,7
H9: 3,7                                  # 10 pairs
I9: 3,7,6                                # reduction candidate for 3,7
I9: 3,7                                  # 14 pairs
* PAIR C9: 3,7 COL C
C1: 3,7,8                                # reduction candidate for 3,7
C1: 3,7                                  # 10 pairs
C3: 3,7,8                                # reduction candidate for 3,7
C3: 3,7 => SOLVED
* 148735296795612384263894715879346152354921678621587439986473521532169847417258963
C3: 8                                    # 10 pairs
* PAIR F8: 3,9 ROW 8
B8: 3,9,7                                # reduction candidate for 3,9
B8: 3,9 => SOLVED
* 148735296795612384263894715879346152354921678621587439986473521532169847417258963
B8: 7 => CTR
* 14.385296395612784268794315739846152.549216...215374.99864735215721698434132589..
* PAIR I8: 3,7 BLK 9
H9: 3,7,6                                # reduction candidate for 3,7
H9: 3,7                                  # 10 pairs
I9: 3,7,6                                # reduction candidate for 3,7
I9: 3,7                                  # 14 pairs
* PAIR I8: 3,7 ROW 8
B8: 3,7,9                                # reduction candidate for 3,7
B8: 9 => CTR
* 14.7.52969.5.12.842...94.15739846152.5492167..215.74.9.8647.5215921638474172589..
B8: 3,7                                  #  9 pairs
* PAIR I8: 3,7 COL I
I1: 3,7,6,8                              # reduction candidate for 3,7
I1: 3,7                                  # 15 pairs
I5: 3,7,6,8                              # reduction candidate for 3,7
I5: 3,7 => CTR
* 14...5298..5812..42.8.94.15879346152.54921.8..215874.9.8647.5215.216.8474172589.6
I5: 6,8                                  # 10 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-445-base-pr-000.dot
* REASONING
* DIS # D1: 3,8 => CTR => D1: 6,7
* DIS # I1: 3,8 => CTR => I1: 6,7
* PRF # A4: 8 => SOL
* DIS # B2: 3,7 => CTR => B2: 6,9
* DIS # B3: 3,7 => CTR => B3: 6
* PRF # A4: 3,8 => SOL
* DIS # D1: 3,8 => CTR => D1: 6,7
* PRF # B8: 3,9 => SOL
* DIS # B8: 7 => CTR => B8: 3,9
* PRF # A2: 7 => SOL
* DIS # B8: 9 => CTR => B8: 3,7
* PRF # C3: 3,7 => SOL
* PRF # B8: 3,9 => SOL
* DIS # B8: 7 => CTR => B8: 3,9
* DIS # B8: 9 => CTR => B8: 3,7
* DIS # I5: 3,7 => CTR => I5: 6,8
* CNT  16 HDP CHAINS /  42 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A7,B4,C9,D4,E1,E6,F7,F8,I8)
* 14...529...5.12..42...94.15..9.46152.54921....215.74.9.8647.5215.216.84.41.2589..
* PAIR E1: 3,8 BLK 2
D1: 3,8,6,7                              # reduction candidate for 3,8
D1: 3,8 => CTR
* 147835296..5.12.842.8.94.15..9.46152.549216.8621587439.8647.5215.216.84.41.25896.
D2: 3,8,6,7                              # reduction candidate for 3,8
D2: 3,8                                  # 13 pairs
D3: 3,8,6,7                              # reduction candidate for 3,8
D3: 3,8                                  # 14 pairs
* PAIR E1: 3,8 ROW 1
C1: 3,8,7                                # reduction candidate for 3,8
C1: 3,8                                  # 16 pairs
I1: 3,8,6,7                              # reduction candidate for 3,8
I1: 3,8 => CTR
* 1476.529...5.12..42.8.94.15739846152.54921....215374.9.8647.5215721698434132589..
* RESTART
* PAIR RESTART
* PAIR E1: 3,8 BLK 2
D3: 3,8,6,7                              # reduction candidate for 3,8
D3: 6,7 => CTR
* 14..8529...5312.842.8.94315..9846152.54921..8821537469.8647.5215.216.84.4172589..
* PAIR B4: 3,7 BLK 4
A4: 3,7,8                                # reduction candidate for 3,7
A4: 3,7 => CTR
* 14...529...5.12.842...94.15..9846152.54921..8821537469.8647.5215.216.84.41.258976
A4: 8 => SOLVED
* 148735296795612384263894715879346152354921678621587439986473521532169847417258963
* DURATION: 0:00:10.298091  START: 17:58:42.318147  END: 17:58:52.616238 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-445-base-pr-001.dot
* REASONING
* DIS # D1: 3,8 => CTR => D1: 6,7
* DIS D1: 6,7 # I1: 3,8 => CTR => I1: 6,7
* DIS D1: 6,7 + I1: 6,7 # D3: 6,7 => CTR => D3: 3,8
* DIS D1: 6,7 + I1: 6,7 + D3: 3,8 # A4: 3,7 => CTR => A4: 8
* PRF D1: 6,7 + I1: 6,7 + D3: 3,8 + A4: 8 => SOL
* STA D1: 6,7 + I1: 6,7 + D3: 3,8 + A4: 8
* CNT   5 HDP CHAINS /   8 HYP OPENED

Header Info

Top 500 Minimum 17 445

solution: 148735296795612384263894715879346152354921678621587439986473521532169847417258963
info: 95318    FNBXYK   S8.f     25166

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

Solution

position: 148735296795612384263894715879346152354921678621587439986473521532169847417258963 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 # D1: 3,8 => CTR => D1: 6,7
* INC # D1: 6,7 => UNS
* INC # D2: 3,8 => UNS
* INC # D3: 3,8 => UNS
* INC # C1: 3,8 => UNS
* DIS # I1: 3,8 => CTR => I1: 6,7
* INC # I1: 6,7 => UNS
* INC # A4: 3,7 => UNS
* PRF # A4: 8 => SOL
* DIS # B2: 3,7 => CTR => B2: 6,9
* INC # B2: 6,9 => UNS
* DIS # B3: 3,7 => CTR => B3: 6
* INC # B3: 6 => UNS
* INC # B8: 3,7 => UNS
* PRF # A4: 3,8 => SOL
* INC # A4: 7 => UNS
* DIS # D1: 3,8 => CTR => D1: 6,7
* INC # D1: 6,7 => UNS
* INC # D2: 3,8 => UNS
* INC # D3: 3,8 => UNS
* INC # A6: 3,8 => UNS
* INC # H6: 3,8 => UNS
* PRF # B8: 3,9 => SOL
* DIS # B8: 7 => CTR => B8: 3,9
* INC # A2: 3,9 => UNS
* PRF # A2: 7 => SOL
* INC # B8: 3,7 => UNS
* DIS # B8: 9 => CTR => B8: 3,7
* INC # H9: 3,7 => UNS
* INC # I9: 3,7 => UNS
* INC # C1: 3,7 => UNS
* PRF # C3: 3,7 => SOL
* INC # C3: 8 => UNS
* PRF # B8: 3,9 => SOL
* DIS # B8: 7 => CTR => B8: 3,9
* INC # H9: 3,7 => UNS
* INC # I9: 3,7 => UNS
* INC # B8: 3,7 => UNS
* DIS # B8: 9 => CTR => B8: 3,7
* INC # I1: 3,7 => UNS
* DIS # I5: 3,7 => CTR => I5: 6,8
* INC # I5: 6,8 => UNS
* CNT  42 HDP CHAINS /  42 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # D1: 3,8 => CTR => D1: 6,7
* INC D1: 6,7 # D2: 3,8 => UNS
* INC D1: 6,7 # D3: 3,8 => UNS
* INC D1: 6,7 # C1: 3,8 => UNS
* DIS D1: 6,7 # I1: 3,8 => CTR => I1: 6,7
* INC D1: 6,7 + I1: 6,7 # D3: 3,8 => UNS
* DIS D1: 6,7 + I1: 6,7 # D3: 6,7 => CTR => D3: 3,8
* DIS D1: 6,7 + I1: 6,7 + D3: 3,8 # A4: 3,7 => CTR => A4: 8
* PRF D1: 6,7 + I1: 6,7 + D3: 3,8 + A4: 8 => SOL
* STA D1: 6,7 + I1: 6,7 + D3: 3,8 + A4: 8
* CNT   9 HDP CHAINS /   8 HYP OPENED