Analysis of xx-top500-274-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ...6.7.....24......3....8...5..3..2.6.......4....1....7.....3..4..7............5. initial

Autosolve

position: .4.6572.3.6248357.537.2.846.54.3672.62.57..3437.2146.57.5.4236.4.3765..22.639.457 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # A1: 1,9 => CTR => A1: 8
* DIS # A4: 8 => CTR => A4: 1,9
* DIS # A1: 1,9 => CTR => A1: 8
* PRF # H8: 1,9 => SOL
* DIS # H8: 8 => CTR => H8: 1,9
* PRF # I4: 1,9 => SOL
* DIS # I4: 8 => CTR => I4: 1,9
* DIS # I7: 1,9 => CTR => I7: 8
* PRF # I7: 8 => SOL
* DIS # A4: 8,9 => CTR => A4: 1
* PRF # A4: 1 => SOL
* PRF # C5: 8,9 => SOL
* DIS # C5: 1 => CTR => C5: 8,9
* DIS # C1: 8,9 => CTR => C1: 1
* PRF # C1: 1 => SOL
* DIS # A4: 8,9 => CTR => A4: 1
* PRF # A4: 1 => SOL
* PRF # I4: 8,9 => SOL
* DIS # I4: 1 => CTR => I4: 8,9
* PRF # C5: 8,9 => SOL
* DIS # C5: 1 => CTR => C5: 8,9
* PRF # I4: 1,9 => SOL
* DIS # I4: 8 => CTR => I4: 1,9
* DIS # C5: 1,9 => CTR => C5: 8
* PRF # C5: 8 => SOL
* PRF # I4: 8,9 => SOL
* DIS # I4: 1 => CTR => I4: 8,9
* DIS # H8: 8,9 => CTR => H8: 1
* PRF # H8: 1 => SOL
* DIS # B7: 1,8 => CTR => B7: 9
* DIS # B7: 1,8 => CTR => B7: 9
* DIS # I7: 1,9 => CTR => I7: 8
* PRF # I7: 8 => SOL
* PRF # H8: 1,9 => SOL
* DIS # H8: 8 => CTR => H8: 1,9
* DIS # B8: 1,9 => CTR => B8: 8
* PRF # B8: 8 => SOL
* CNT  37 HDP CHAINS /  46 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 # A1: 1,9 => CTR => A1: 8
* PRF A1: 8 # H8: 1,9 => SOL
* STA A1: 8 + H8: 1,9
* CNT   2 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

...6.7.....24......3....8...5..3..2.6.......4....1....7.....3..4..7............5. initial
.4.6572.3.6248357.537.2.846.54.3672.62.57..3437.2146.57.5.4236.4.3765..22.639.457 autosolve
841657293962483571537921846154836729628579134379214685795142368483765912216398457 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (14)
A2: 1,9
D3: 1,9
F3: 1,9
H1: 1,9
I2: 1,9
C6: 8,9
D4: 8,9
F5: 8,9
G5: 1,9
H6: 8,9
B9: 1,8
D7: 1,8
F9: 1,8
G8: 1,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
D3,F3: 1.. / D3 = 1  =>  0 pairs (X) / F3 = 1  =>  0 pairs (_)
H1,I2: 1.. / H1 = 1  =>  0 pairs (X) / I2 = 1  =>  0 pairs (_)
A4,C5: 1.. / A4 = 1  =>  0 pairs (*) / C5 = 1  =>  0 pairs (X)
I4,G5: 1.. / I4 = 1  =>  0 pairs (X) / G5 = 1  =>  0 pairs (_)
D7,F9: 1.. / D7 = 1  =>  0 pairs (*) / F9 = 1  =>  0 pairs (X)
A2,I2: 1.. / A2 = 1  =>  0 pairs (X) / I2 = 1  =>  0 pairs (_)
A4,I4: 1.. / A4 = 1  =>  0 pairs (*) / I4 = 1  =>  0 pairs (X)
C5,G5: 1.. / C5 = 1  =>  0 pairs (X) / G5 = 1  =>  0 pairs (_)
B9,F9: 1.. / B9 = 1  =>  0 pairs (*) / F9 = 1  =>  0 pairs (X)
C1,C5: 1.. / C1 = 1  =>  0 pairs (*) / C5 = 1  =>  0 pairs (X)
D3,D7: 1.. / D3 = 1  =>  0 pairs (X) / D7 = 1  =>  0 pairs (_)
F3,F9: 1.. / F3 = 1  =>  0 pairs (*) / F9 = 1  =>  0 pairs (X)
G5,G8: 1.. / G5 = 1  =>  0 pairs (*) / G8 = 1  =>  0 pairs (X)
H1,H8: 1.. / H1 = 1  =>  0 pairs (X) / H8 = 1  =>  0 pairs (_)
A1,C1: 8.. / A1 = 8  => 16 pairs (_) / C1 = 8  =>  0 pairs (X)
D4,F5: 8.. / D4 = 8  =>  0 pairs (*) / F5 = 8  =>  0 pairs (X)
I4,H6: 8.. / I4 = 8  =>  0 pairs (X) / H6 = 8  =>  0 pairs (_)
D7,F9: 8.. / D7 = 8  =>  0 pairs (X) / F9 = 8  =>  0 pairs (_)
I7,H8: 8.. / I7 = 8  =>  0 pairs (*) / H8 = 8  =>  0 pairs (X)
C5,F5: 8.. / C5 = 8  =>  0 pairs (*) / F5 = 8  =>  0 pairs (X)
C6,H6: 8.. / C6 = 8  =>  0 pairs (X) / H6 = 8  =>  0 pairs (_)
B8,H8: 8.. / B8 = 8  =>  0 pairs (*) / H8 = 8  =>  0 pairs (X)
B9,F9: 8.. / B9 = 8  =>  0 pairs (X) / F9 = 8  =>  0 pairs (_)
A1,A4: 8.. / A1 = 8  => 16 pairs (_) / A4 = 8  =>  0 pairs (X)
D4,D7: 8.. / D4 = 8  =>  0 pairs (*) / D7 = 8  =>  0 pairs (X)
F5,F9: 8.. / F5 = 8  =>  0 pairs (X) / F9 = 8  =>  0 pairs (_)
H6,H8: 8.. / H6 = 8  =>  0 pairs (*) / H8 = 8  =>  0 pairs (X)
I4,I7: 8.. / I4 = 8  =>  0 pairs (X) / I7 = 8  =>  0 pairs (_)
D3,F3: 9.. / D3 = 9  =>  0 pairs (*) / F3 = 9  =>  0 pairs (X)
H1,I2: 9.. / H1 = 9  =>  0 pairs (*) / I2 = 9  =>  0 pairs (X)
D4,F5: 9.. / D4 = 9  =>  0 pairs (X) / F5 = 9  =>  0 pairs (_)
B7,B8: 9.. / B7 = 9  => 16 pairs (_) / B8 = 9  =>  0 pairs (X)
A2,I2: 9.. / A2 = 9  =>  0 pairs (*) / I2 = 9  =>  0 pairs (X)
C6,H6: 9.. / C6 = 9  =>  0 pairs (*) / H6 = 9  =>  0 pairs (X)
B7,I7: 9.. / B7 = 9  => 16 pairs (_) / I7 = 9  =>  0 pairs (X)
D3,D4: 9.. / D3 = 9  =>  0 pairs (*) / D4 = 9  =>  0 pairs (X)
F3,F5: 9.. / F3 = 9  =>  0 pairs (X) / F5 = 9  =>  0 pairs (_)
G5,G8: 9.. / G5 = 9  =>  0 pairs (X) / G8 = 9  =>  0 pairs (_)
* DURATION: 0:01:19.568454  START: 12:17:00.178331  END: 12:18:19.746785 2017-05-04
* CP COUNT: (38)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,B9,C6,D3,D4,D7,F3,F5,F9,G5,G8,H1,H6,I2)
* .4.6572.3.6248357.537.2.846.54.3672.62.57..3437.2146.57.5.4236.4.3765..22.639.457
* PAIR A2: 1,9 BLK 1
A1: 1,9,8                                # reduction candidate for 1,9
A1: 1,9 => CTR
* .486572.3.6248357.537.2.8468549367216215789343792146857.58423694.3765..22.639.457
A1: 8                                    # 16 pairs
C1: 1,9,8                                # reduction candidate for 1,9
C1: 1,9                                  # 16 pairs
* PAIR A2: 1,9 COL A
A4: 1,9,8                                # reduction candidate for 1,9
A4: 8 => CTR
* .4.6572.3.6248357.537.2.8468549367216215789343792146857.58423694.3765..22.639.457
A4: 1,9                                  # 16 pairs
* PAIR H1: 1,9 ROW 1
A1: 1,9,8                                # reduction candidate for 1,9
A1: 1,9 => CTR
* .486572.3.6248357.537.2.8468549367216215789343792146857.58423694.3765..22.639.457
A1: 8                                    # 16 pairs
C1: 1,9,8                                # reduction candidate for 1,9
C1: 1,9                                  # 16 pairs
* PAIR H1: 1,9 COL H
H8: 1,9,8                                # reduction candidate for 1,9
H8: 1,9 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
H8: 8 => CTR
* .4.657213162483579537.2.846.54.3672162157893437.2146.57.5.4236.4.3765..22.639.457
* PAIR I2: 1,9 COL I
I4: 1,9,8                                # reduction candidate for 1,9
I4: 1,9 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
I4: 8 => CTR
* .4.6572.3.6248357.537.2.84615493672862.5781343782146957.584236.4.3765982286391457
I7: 1,9,8                                # reduction candidate for 1,9
I7: 1,9 => CTR
* 84.6572.3.6248357.537.2.846.54.3672862.5781343782146957.584236.4.3765982286391457
I7: 8 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
* PAIR C6: 8,9 BLK 4
A4: 8,9,1                                # reduction candidate for 8,9
A4: 8,9 => CTR
* .4.6572.3.6248357.537.2.846.54.367216215789343792146857.58423694.3765..22.639.457
A4: 1 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
C5: 8,9,1                                # reduction candidate for 8,9
C5: 8,9 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
C5: 1 => CTR
* .4.6572.3.6248357.537.2.846.54.3672.6215789343792146857.584236.4837651922.639.457
* PAIR C6: 8,9 COL C
C1: 8,9,1                                # reduction candidate for 8,9
C1: 8,9 => CTR
* .4.6572.3.6248357.537.2.846.54.3672.6215789343792146857.584236.4837651922.639.457
C1: 1 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
* PAIR D4: 8,9 ROW 4
A4: 8,9,1                                # reduction candidate for 8,9
A4: 8,9 => CTR
* .4.6572.3.6248357.537.2.846.54.367216215789343792146857.58423694.3765..22.639.457
A4: 1 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
I4: 8,9,1                                # reduction candidate for 8,9
I4: 8,9 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
I4: 1 => CTR
* .4.6572.3.6248357.537.2.846.54.367216215789343792146857.58423694.3765..22.639.457
* PAIR F5: 8,9 ROW 5
C5: 8,9,1                                # reduction candidate for 8,9
C5: 8,9 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
C5: 1 => CTR
* .4.6572.3.6248357.537.2.846.54.3672.6215789343792146857.584236.4837651922.639.457
* PAIR G5: 1,9 BLK 6
I4: 1,9,8                                # reduction candidate for 1,9
I4: 1,9 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
I4: 8 => CTR
* .4.6572.3.6248357.537.2.84615493672862.5781343782146957.584236.4.3765982286391457
* PAIR G5: 1,9 ROW 5
C5: 1,9,8                                # reduction candidate for 1,9
C5: 1,9 => CTR
* .4.657213162483579537.2.846.54.3672.62.578.3437.2146.57.584236.4.3765.82286391457
C5: 8 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
* PAIR H6: 8,9 BLK 6
I4: 8,9,1                                # reduction candidate for 8,9
I4: 8,9 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
I4: 1 => CTR
* .4.6572.3.6248357.537.2.846.54.367216215789343792146857.58423694.3765..22.639.457
* PAIR H6: 8,9 COL H
H8: 8,9,1                                # reduction candidate for 8,9
H8: 8,9 => CTR
* .4.657213162483579537.2.846.54.36721621578934379214685795.4236.4.3765..22.639.457
H8: 1 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
* PAIR B9: 1,8 BLK 7
B7: 1,8,9                                # reduction candidate for 1,8
B7: 1,8 => CTR
* .4.6572.3.6248357.537.2.846.54.3672.62.57..3437.2146.57.5.423694937651822.639.457
B7: 9                                    # 16 pairs
B8: 1,8,9                                # reduction candidate for 1,8
B8: 1,8                                  # 16 pairs
* PAIR D7: 1,8 ROW 7
B7: 1,8,9                                # reduction candidate for 1,8
B7: 1,8 => CTR
* .4.6572.3.6248357.537.2.846.54.3672.62.57..3437.2146.57.5.423694937651822.639.457
B7: 9                                    # 16 pairs
I7: 1,8,9                                # reduction candidate for 1,8
I7: 1,8                                  # 16 pairs
* PAIR G8: 1,9 BLK 9
I7: 1,9,8                                # reduction candidate for 1,9
I7: 1,9 => CTR
* 84.6572.3.6248357.537.2.846.54.3672862.5781343782146957.584236.4.3765982286391457
I7: 8 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
H8: 1,9,8                                # reduction candidate for 1,9
H8: 1,9 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
H8: 8 => CTR
* .4.657213162483579537.2.846.54.3672162157893437.2146.57.5.4236.4.3765..22.639.457
* PAIR G8: 1,9 ROW 8
B8: 1,9,8                                # reduction candidate for 1,9
B8: 1,9 => CTR
* .4.657213162483579537.2.846.54.3672.62.57..3437.2146.57.5.4236.4.3765.822.639.457
B8: 8 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-274-base-pr-000.dot
* REASONING
* DIS # A1: 1,9 => CTR => A1: 8
* DIS # A4: 8 => CTR => A4: 1,9
* DIS # A1: 1,9 => CTR => A1: 8
* PRF # H8: 1,9 => SOL
* DIS # H8: 8 => CTR => H8: 1,9
* PRF # I4: 1,9 => SOL
* DIS # I4: 8 => CTR => I4: 1,9
* DIS # I7: 1,9 => CTR => I7: 8
* PRF # I7: 8 => SOL
* DIS # A4: 8,9 => CTR => A4: 1
* PRF # A4: 1 => SOL
* PRF # C5: 8,9 => SOL
* DIS # C5: 1 => CTR => C5: 8,9
* DIS # C1: 8,9 => CTR => C1: 1
* PRF # C1: 1 => SOL
* DIS # A4: 8,9 => CTR => A4: 1
* PRF # A4: 1 => SOL
* PRF # I4: 8,9 => SOL
* DIS # I4: 1 => CTR => I4: 8,9
* PRF # C5: 8,9 => SOL
* DIS # C5: 1 => CTR => C5: 8,9
* PRF # I4: 1,9 => SOL
* DIS # I4: 8 => CTR => I4: 1,9
* DIS # C5: 1,9 => CTR => C5: 8
* PRF # C5: 8 => SOL
* PRF # I4: 8,9 => SOL
* DIS # I4: 1 => CTR => I4: 8,9
* DIS # H8: 8,9 => CTR => H8: 1
* PRF # H8: 1 => SOL
* DIS # B7: 1,8 => CTR => B7: 9
* DIS # B7: 1,8 => CTR => B7: 9
* DIS # I7: 1,9 => CTR => I7: 8
* PRF # I7: 8 => SOL
* PRF # H8: 1,9 => SOL
* DIS # H8: 8 => CTR => H8: 1,9
* DIS # B8: 1,9 => CTR => B8: 8
* PRF # B8: 8 => SOL
* CNT  37 HDP CHAINS /  46 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,B9,C6,D3,D4,D7,F3,F5,F9,G5,G8,H1,H6,I2)
* .4.6572.3.6248357.537.2.846.54.3672.62.57..3437.2146.57.5.4236.4.3765..22.639.457
* PAIR A2: 1,9 BLK 1
A1: 1,9,8                                # reduction candidate for 1,9
A1: 1,9 => CTR
* .486572.3.6248357.537.2.8468549367216215789343792146857.58423694.3765..22.639.457
* RESTART
* PAIR H1: 1,9 COL H
H8: 1,9,8                                # reduction candidate for 1,9
H8: 1,9 => SOLVED
* 841657293962483571537921846154836729628579134379214685795142368483765912216398457
* DURATION: 0:00:03.717800  START: 12:19:22.347025  END: 12:19:26.064825 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-274-base-pr-001.dot
* REASONING
* DIS # A1: 1,9 => CTR => A1: 8
* PRF A1: 8 # H8: 1,9 => SOL
* STA A1: 8 + H8: 1,9
* CNT   2 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 274

solution: 841657293962483571537921846154836729628579134379214685795142368483765912216398457
info: 2203     FNBHWY   S8.f     10921

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

Solution

position: 841657293962483571537921846154836729628579134379214685795142368483765912216398457 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 # A1: 1,9 => CTR => A1: 8
* INC # A1: 8 => UNS
* INC # C1: 1,9 => UNS
* INC # A4: 1,9 => UNS
* DIS # A4: 8 => CTR => A4: 1,9
* DIS # A1: 1,9 => CTR => A1: 8
* INC # A1: 8 => UNS
* INC # C1: 1,9 => UNS
* PRF # H8: 1,9 => SOL
* DIS # H8: 8 => CTR => H8: 1,9
* PRF # I4: 1,9 => SOL
* DIS # I4: 8 => CTR => I4: 1,9
* DIS # I7: 1,9 => CTR => I7: 8
* PRF # I7: 8 => SOL
* DIS # A4: 8,9 => CTR => A4: 1
* PRF # A4: 1 => SOL
* PRF # C5: 8,9 => SOL
* DIS # C5: 1 => CTR => C5: 8,9
* DIS # C1: 8,9 => CTR => C1: 1
* PRF # C1: 1 => SOL
* DIS # A4: 8,9 => CTR => A4: 1
* PRF # A4: 1 => SOL
* PRF # I4: 8,9 => SOL
* DIS # I4: 1 => CTR => I4: 8,9
* PRF # C5: 8,9 => SOL
* DIS # C5: 1 => CTR => C5: 8,9
* PRF # I4: 1,9 => SOL
* DIS # I4: 8 => CTR => I4: 1,9
* DIS # C5: 1,9 => CTR => C5: 8
* PRF # C5: 8 => SOL
* PRF # I4: 8,9 => SOL
* DIS # I4: 1 => CTR => I4: 8,9
* DIS # H8: 8,9 => CTR => H8: 1
* PRF # H8: 1 => SOL
* DIS # B7: 1,8 => CTR => B7: 9
* INC # B7: 9 => UNS
* INC # B8: 1,8 => UNS
* DIS # B7: 1,8 => CTR => B7: 9
* INC # B7: 9 => UNS
* INC # I7: 1,8 => UNS
* DIS # I7: 1,9 => CTR => I7: 8
* PRF # I7: 8 => SOL
* PRF # H8: 1,9 => SOL
* DIS # H8: 8 => CTR => H8: 1,9
* DIS # B8: 1,9 => CTR => B8: 8
* PRF # B8: 8 => SOL
* CNT  46 HDP CHAINS /  46 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # A1: 1,9 => CTR => A1: 8
* PRF A1: 8 # H8: 1,9 => SOL
* STA A1: 8 + H8: 1,9
* CNT   2 HDP CHAINS /   2 HYP OPENED