Analysis of xx-top500-424-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .6....3....89.................56..7.12.......3...7..........6.3..94..........12.. initial

Autosolve

position: .6....3....89................45631721278..536356172.........6.3..94..........12.. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # E9: 3,5 => CTR => E9: 8,9
* DIS # C3: 1,2 => CTR => C3: 3,5
* DIS # B8: 7,8 => CTR => B8: 1,3
* DIS # F8: 7,8 => CTR => F8: 5,6
* CNT   4 HDP CHAINS /  24 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 # E9: 3,5 => CTR => E9: 8,9
* DIS E9: 8,9 # C3: 1,2 => CTR => C3: 3,5
* DIS E9: 8,9 + C3: 3,5 # A7: 2,7 => CTR => A7: 4,5,8
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 # B8: 7,8 => CTR => B8: 1,3
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 # F8: 7,8 => CTR => F8: 5,6
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # E1: 1,2 => CTR => E1: 4,5,8
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 # H1: 1,2 => CTR => H1: 4,5,8,9
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 # E3: 3,5 => CTR => E3: 1,2,4,8
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 + E3: 1,2,4,8 # A1: 2,7 => CTR => A1: 4,5,9
* PRF E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 + E3: 1,2,4,8 + A1: 4,5,9 # I1: 4,7 => SOL
* STA E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 + E3: 1,2,4,8 + A1: 4,5,9 + I1: 4,7
* CNT  10 HDP CHAINS /  33 HYP OPENED

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

Details

Positions

.6....3....89.................56..7.12.......3...7..........6.3..94..........12.. initial
.6....3....89................45631721278..536356172.........6.3..94..........12.. autosolve
961287354248935761573614928894563172127849536356172489412758693739426815685391247 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (11)
D1: 2,7
D3: 3,6
G2: 4,7
A4: 8,9
B4: 8,9
E5: 4,9
F5: 4,9
C9: 3,5
D7: 2,7
D9: 3,6
G8: 7,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
A8,E8: 2.. / A8 = 2  =>  0 pairs (X) / E8 = 2  => 12 pairs (_)
D1,D7: 2.. / D1 = 2  => 12 pairs (_) / D7 = 2  =>  0 pairs (X)
B2,E2: 3.. / B2 = 3  =>  0 pairs (X) / E2 = 3  => 12 pairs (_)
B8,E8: 3.. / B8 = 3  => 12 pairs (_) / E8 = 3  =>  0 pairs (X)
C3,C9: 3.. / C3 = 3  => 12 pairs (_) / C9 = 3  =>  0 pairs (X)
D3,D9: 3.. / D3 = 3  =>  0 pairs (X) / D9 = 3  => 12 pairs (_)
E5,F5: 4.. / E5 = 4  =>  9 pairs (_) / F5 = 4  =>  9 pairs (_)
H2,H3: 6.. / H2 = 6  => 11 pairs (_) / H3 = 6  =>  0 pairs (X)
A8,A9: 6.. / A8 = 6  =>  0 pairs (X) / A9 = 6  => 12 pairs (_)
F8,D9: 6.. / F8 = 6  => 12 pairs (_) / D9 = 6  =>  0 pairs (X)
F2,H2: 6.. / F2 = 6  =>  0 pairs (X) / H2 = 6  => 11 pairs (_)
A8,F8: 6.. / A8 = 6  =>  0 pairs (X) / F8 = 6  => 12 pairs (_)
A9,D9: 6.. / A9 = 6  => 12 pairs (_) / D9 = 6  =>  0 pairs (X)
D3,D9: 6.. / D3 = 6  => 12 pairs (_) / D9 = 6  =>  0 pairs (X)
D1,D7: 7.. / D1 = 7  =>  0 pairs (X) / D7 = 7  => 12 pairs (_)
A4,B4: 8.. / A4 = 8  =>  9 pairs (_) / B4 = 8  => 11 pairs (_)
A4,B4: 9.. / A4 = 9  => 11 pairs (_) / B4 = 9  =>  9 pairs (_)
E5,F5: 9.. / E5 = 9  =>  9 pairs (_) / F5 = 9  =>  9 pairs (_)
B3,B4: 9.. / B3 = 9  => 11 pairs (_) / B4 = 9  =>  9 pairs (_)
F5,F7: 9.. / F5 = 9  =>  9 pairs (_) / F7 = 9  =>  9 pairs (_)
G3,G6: 9.. / G3 = 9  => 10 pairs (_) / G6 = 9  => 13 pairs (_)
* DURATION: 0:00:27.201566  START: 17:17:33.564090  END: 17:18:00.765656 2017-05-04
* CP COUNT: (21)
* CLUE FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,B4,C9,D1,D3,D7,D9,E5,F5,G2,G8)
* .6....3....89................45631721278..536356172.........6.3..94..........12..
* PAIR D1: 2,7 ROW 1
A1: 2,7,4,5,9                            # reduction candidate for 2,7
A1: 2,7                                  # 17 pairs
A1: 4,5,9                                # 11 pairs
* PAIR G2: 4,7 BLK 3
I1: 4,7,1,5,8,9                          # reduction candidate for 4,7
I1: 4,7                                  # 14 pairs
I2: 4,7,1,5                              # reduction candidate for 4,7
I2: 4,7                                  # 16 pairs
G3: 4,7,8,9                              # reduction candidate for 4,7
G3: 4,7                                  # 15 pairs
I3: 4,7,1,5,8,9                          # reduction candidate for 4,7
I3: 4,7                                  # 14 pairs
* PAIR G2: 4,7 ROW 2
A2: 4,7,2,5                              # reduction candidate for 4,7
A2: 4,7                                  # 15 pairs
B2: 4,7,1,3                              # reduction candidate for 4,7
B2: 4,7                                  # 12 pairs
F2: 4,7,5,6                              # reduction candidate for 4,7
F2: 4,7                                  # 15 pairs
* PAIR C9: 3,5 ROW 9
E9: 3,5,8,9                              # reduction candidate for 3,5
E9: 3,5 => CTR
* .6....3....89........3.......45631721278..536356172.........6.36.942......36512..
E9: 8,9                                  # 12 pairs
* PAIR C9: 3,5 COL C
C3: 3,5,1,2                              # reduction candidate for 3,5
C3: 1,2 => CTR
* .6....3....89........3.......45631721278..536356172.........6.36.94.......36.12..
C3: 3,5                                  # 14 pairs
* PAIR D7: 2,7 ROW 7
A7: 2,7,4,5,8                            # reduction candidate for 2,7
A7: 2,7                                  # 13 pairs
A7: 4,5,8                                # 11 pairs
* PAIR G8: 7,8 BLK 9
I8: 7,8,1,5                              # reduction candidate for 7,8
I8: 7,8                                  # 15 pairs
I9: 7,8,4,5,9                            # reduction candidate for 7,8
I9: 7,8                                  # 18 pairs
* PAIR G8: 7,8 ROW 8
A8: 7,8,2,5,6                            # reduction candidate for 7,8
A8: 7,8                                  # 12 pairs
B8: 7,8,1,3                              # reduction candidate for 7,8
B8: 7,8 => CTR
* .6....3....89................45631721278..536356172.........6.3..943.......6.12..
B8: 1,3                                  # 12 pairs
F8: 7,8,5,6                              # reduction candidate for 7,8
F8: 7,8 => CTR
* .6.2..3...389........3.......45631721278..536356172......7..6.36.94287....56312..
F8: 5,6                                  # 12 pairs
* PAIR G8: 7,8 COL G
G3: 7,8,4,9                              # reduction candidate for 7,8
G3: 7,8                                  # 13 pairs
G3: 4,9                                  # 12 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-424-base-pr-000.dot
* REASONING
* DIS # E9: 3,5 => CTR => E9: 8,9
* DIS # C3: 1,2 => CTR => C3: 3,5
* DIS # B8: 7,8 => CTR => B8: 1,3
* DIS # F8: 7,8 => CTR => F8: 5,6
* CNT   4 HDP CHAINS /  24 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A4,B4,C9,D1,D3,D7,D9,E5,F5,G2,G8)
* .6....3....89................45631721278..536356172.........6.3..94..........12..
* PAIR D1: 2,7 ROW 1
A1: 2,7,4,5,9                            # reduction candidate for 2,7
A1: 2,7                                  # 17 pairs
A1: 4,5,9                                # 11 pairs
* PAIR G2: 4,7 BLK 3
I1: 4,7,1,5,8,9                          # reduction candidate for 4,7
I1: 4,7                                  # 14 pairs
I2: 4,7,1,5                              # reduction candidate for 4,7
I2: 4,7                                  # 16 pairs
G3: 4,7,8,9                              # reduction candidate for 4,7
G3: 4,7                                  # 15 pairs
I3: 4,7,1,5,8,9                          # reduction candidate for 4,7
I3: 4,7                                  # 14 pairs
* PAIR G2: 4,7 ROW 2
A2: 4,7,2,5                              # reduction candidate for 4,7
A2: 4,7                                  # 15 pairs
B2: 4,7,1,3                              # reduction candidate for 4,7
B2: 4,7                                  # 12 pairs
F2: 4,7,5,6                              # reduction candidate for 4,7
F2: 4,7                                  # 15 pairs
* PAIR C9: 3,5 ROW 9
E9: 3,5,8,9                              # reduction candidate for 3,5
E9: 3,5 => CTR
* .6....3....89........3.......45631721278..536356172.........6.36.942......36512..
* PAIR C9: 3,5 COL C
C3: 3,5,1,2                              # reduction candidate for 3,5
C3: 1,2 => CTR
* .6....3....89........3.......45631721278..536356172.........6.36.94.......36.12..
* PAIR RESTART
* PAIR D7: 2,7 ROW 7
A7: 2,7,4,5,8                            # reduction candidate for 2,7
A7: 2,7 => CTR
* .627..3....89................45631721278..536356172...7.12..6.32.94..........12..
* PAIR RESTART
* PAIR G8: 7,8 BLK 9
I8: 7,8,1,5                              # reduction candidate for 7,8
I8: 7,8                                  # 19 pairs
I9: 7,8,4,5,9                            # reduction candidate for 7,8
I9: 7,8                                  # 23 pairs
* PAIR G8: 7,8 ROW 8
A8: 7,8,2,5,6                            # reduction candidate for 7,8
A8: 7,8                                  # 12 pairs
B8: 7,8,1,3                              # reduction candidate for 7,8
B8: 7,8 => CTR
* .6....3....89................45631721278..536356172.........6.3..943.......6.12..
F8: 7,8,5,6                              # reduction candidate for 7,8
F8: 7,8 => CTR
* .6....3....89................45631721278..536356172.........6.36.942.........12..
* RESTART
* PAIR G8: 7,8 ROW 8
A8: 7,8,2,5,6                            # reduction candidate for 7,8
A8: 2,5,6                                # 17 pairs
A8: 7,8                                  # 12 pairs
* PAIR G8: 7,8 COL G
G3: 7,8,4,9                              # reduction candidate for 7,8
G3: 7,8                                  # 19 pairs
G3: 4,9                                  # 18 pairs
* PAIR RESTART
* PAIR G8: 7,8 BLK 9
I8: 7,8,1,5                              # reduction candidate for 7,8
I8: 7,8                                  # 19 pairs
I9: 7,8,4,5,9                            # reduction candidate for 7,8
I9: 7,8                                  # 17 pairs
* PAIR G8: 7,8 ROW 8
A8: 7,8,2,5,6                            # reduction candidate for 7,8
A8: 2,5,6                                # 17 pairs
A8: 7,8                                  # 12 pairs
* PAIR G8: 7,8 COL G
G3: 7,8,4,9                              # reduction candidate for 7,8
G3: 7,8                                  # 19 pairs
G3: 4,9                                  # 18 pairs

* LEVEL 0 PASS 1 ROUND 2 (AUTO SOLVE) (A4,B4,B8,C1,C3,C7,C9,D1,D3,D7,D9,E5,E9,F5,F8,G2,G8)
* .6....3....89................45631721278..536356172.........6.3..94..........12..
* PAIR C1: 1,2 ROW 1
E1: 1,2,4,5,8                            # reduction candidate for 1,2
E1: 1,2 => CTR
* .6271.3....89...6...36.......45631721278..536356172......2.76.32.94.6...67.3.12..
H1: 1,2,4,5,8,9                          # reduction candidate for 1,2
H1: 1,2 => CTR
* .627..31...89...6...36.......45631721278..536356172......2.76.32.94.6...67.3.12..
* RESTART
* PAIR RESTART
* PAIR C3: 3,5 ROW 3
E3: 3,5,1,2,4,8                          # reduction candidate for 3,5
E3: 3,5 => CTR
* .6.2..3...3891......5.3......45631721278..536356172.....27..6.3.1942......36.12..
* PAIR RESTART
* PAIR D1: 2,7 ROW 1
A1: 2,7,4,5,9                            # reduction candidate for 2,7
A1: 2,7 => CTR
* 7612..3..248935761593617428..45631721278..5363561729....27..6.3.39426.1.6753.12..
* PAIR RESTART
* PAIR G2: 4,7 BLK 3
I1: 4,7,1,5,8,9                          # reduction candidate for 4,7
I1: 4,7 => SOLVED
* 961287354248935761573614928894563172127849536356172489412758693739426815685391247
* DURATION: 0:00:31.969409  START: 17:18:17.177439  END: 17:18:49.146848 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-424-base-pr-001.dot
* REASONING
* DIS # E9: 3,5 => CTR => E9: 8,9
* DIS E9: 8,9 # C3: 1,2 => CTR => C3: 3,5
* DIS E9: 8,9 + C3: 3,5 # A7: 2,7 => CTR => A7: 4,5,8
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 # B8: 7,8 => CTR => B8: 1,3
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 # F8: 7,8 => CTR => F8: 5,6
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # E1: 1,2 => CTR => E1: 4,5,8
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 # H1: 1,2 => CTR => H1: 4,5,8,9
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 # E3: 3,5 => CTR => E3: 1,2,4,8
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 + E3: 1,2,4,8 # A1: 2,7 => CTR => A1: 4,5,9
* PRF E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 + E3: 1,2,4,8 + A1: 4,5,9 # I1: 4,7 => SOL
* STA E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 + E3: 1,2,4,8 + A1: 4,5,9 + I1: 4,7
* CNT  10 HDP CHAINS /  33 HYP OPENED

Header Info

Top 500 Minimum 17 424

solution: 961287354248935761573614928894563172127849536356172489412758693739426815685391247
info: 95139    FNBTHWXYK S8.f     41317

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

Solution

position: 961287354248935761573614928894563172127849536356172489412758693739426815685391247 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 # A1: 2,7 => UNS
* INC # A1: 4,5,9 => UNS
* INC # I1: 4,7 => UNS
* INC # I2: 4,7 => UNS
* INC # G3: 4,7 => UNS
* INC # I3: 4,7 => UNS
* INC # A2: 4,7 => UNS
* INC # B2: 4,7 => UNS
* INC # F2: 4,7 => UNS
* DIS # E9: 3,5 => CTR => E9: 8,9
* INC # E9: 8,9 => UNS
* INC # C3: 3,5 => UNS
* DIS # C3: 1,2 => CTR => C3: 3,5
* INC # A7: 2,7 => UNS
* INC # A7: 4,5,8 => UNS
* INC # I8: 7,8 => UNS
* INC # I9: 7,8 => UNS
* INC # A8: 7,8 => UNS
* DIS # B8: 7,8 => CTR => B8: 1,3
* INC # B8: 1,3 => UNS
* DIS # F8: 7,8 => CTR => F8: 5,6
* INC # F8: 5,6 => UNS
* INC # G3: 7,8 => UNS
* INC # G3: 4,9 => UNS
* CNT  24 HDP CHAINS /  24 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A1: 2,7 => UNS
* INC # A1: 4,5,9 => UNS
* INC # I1: 4,7 => UNS
* INC # I2: 4,7 => UNS
* INC # G3: 4,7 => UNS
* INC # I3: 4,7 => UNS
* INC # A2: 4,7 => UNS
* INC # B2: 4,7 => UNS
* INC # F2: 4,7 => UNS
* DIS # E9: 3,5 => CTR => E9: 8,9
* INC E9: 8,9 # C3: 3,5 => UNS
* DIS E9: 8,9 # C3: 1,2 => CTR => C3: 3,5
* DIS E9: 8,9 + C3: 3,5 # A7: 2,7 => CTR => A7: 4,5,8
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 # I8: 7,8 => UNS
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 # I9: 7,8 => UNS
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 # A8: 7,8 => UNS
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 # B8: 7,8 => CTR => B8: 1,3
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 # F8: 7,8 => CTR => F8: 5,6
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # A8: 7,8 => UNS
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # A8: 2,5,6 => UNS
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # G3: 7,8 => UNS
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # G3: 4,9 => UNS
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # I8: 7,8 => UNS
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # I9: 7,8 => UNS
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # A8: 7,8 => UNS
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # A8: 2,5,6 => UNS
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # G3: 7,8 => UNS
* INC E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # G3: 4,9 => UNS
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 # E1: 1,2 => CTR => E1: 4,5,8
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 # H1: 1,2 => CTR => H1: 4,5,8,9
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 # E3: 3,5 => CTR => E3: 1,2,4,8
* DIS E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 + E3: 1,2,4,8 # A1: 2,7 => CTR => A1: 4,5,9
* PRF E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 + E3: 1,2,4,8 + A1: 4,5,9 # I1: 4,7 => SOL
* STA E9: 8,9 + C3: 3,5 + A7: 4,5,8 + B8: 1,3 + F8: 5,6 + E1: 4,5,8 + H1: 4,5,8,9 + E3: 1,2,4,8 + A1: 4,5,9 + I1: 4,7
* CNT  33 HDP CHAINS /  33 HYP OPENED