Analysis of xx-top500-165-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .2....1.....3.8......4.........1.5..4.......8.7.....3.1.....7..6.5........48..... initial

Autosolve

position: 82..9.1439413.8.5.35.4.18..268913574413...9.8579.84.31132.4978.6851374..7948.231. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* PRF # D1: 6,7 => SOL
* DIS # D1: 5 => CTR => D1: 6,7
* DIS # E3: 6,7 => CTR => E3: 2
* DIS # D1: 5,6 => CTR => D1: 7
* PRF # D1: 7 => SOL
* DIS # H3: 9 => CTR => H3: 2,6
* DIS # E2: 7 => CTR => E2: 2,6
* DIS # I3: 2,7 => CTR => I3: 9
* DIS # E2: 2,7 => CTR => E2: 6
* PRF # E2: 6 => SOL
* PRF # D5: 5,6 => SOL
* DIS # E5: 5,6 => CTR => E5: 7
* PRF # E5: 7 => SOL
* DIS # D5: 2,6 => CTR => D5: 5,7
* PRF # D5: 5,7 => SOL
* DIS # D5: 2,6 => CTR => D5: 5,7
* PRF # D5: 5,7 => SOL
* DIS # H3: 9 => CTR => H3: 2,6
* DIS # D1: 5,6 => CTR => D1: 7
* PRF # D1: 7 => SOL
* PRF # D5: 5,6 => SOL
* DIS # E5: 5,6 => CTR => E5: 7
* PRF # E5: 7 => SOL
* DIS # H3: 2,9 => CTR => H3: 6
* PRF # H3: 6 => SOL
* DIS # I3: 7 => CTR => I3: 2,9
* CNT  26 HDP CHAINS /  34 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 # D1: 6,7 => SOL
* STA D1: 6,7
* CNT   1 HDP CHAINS /   1 HYP OPENED

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

Details

Positions

.2....1.....3.8......4.........1.5..4.......8.7.....3.1.....7..6.5........48..... initial
82..9.1439413.8.5.35.4.18..268913574413...9.8579.84.31132.4978.6851374..7948.231. autosolve
826795143941368257357421869268913574413576928579284631132649785685137492794852316 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (15)
C1: 6,7
C3: 6,7
F1: 5,6
G2: 2,6
I2: 2,7
F5: 5,6
D6: 2,6
H5: 2,6
G6: 2,6
D7: 5,6
E9: 5,6
I7: 5,6
H8: 2,9
I8: 2,9
I9: 5,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
E2,E3: 2.. / E2 = 2  =>  0 pairs (X) / E3 = 2  => 18 pairs (_)
D5,D6: 2.. / D5 = 2  =>  0 pairs (X) / D6 = 2  =>  0 pairs (_)
H5,G6: 2.. / H5 = 2  =>  0 pairs (*) / G6 = 2  =>  0 pairs (X)
H8,I8: 2.. / H8 = 2  =>  0 pairs (X) / I8 = 2  => 14 pairs (_)
D5,H5: 2.. / D5 = 2  =>  0 pairs (X) / H5 = 2  =>  0 pairs (_)
D6,G6: 2.. / D6 = 2  =>  0 pairs (*) / G6 = 2  =>  0 pairs (X)
G2,G6: 2.. / G2 = 2  =>  0 pairs (*) / G6 = 2  =>  0 pairs (X)
D1,F1: 5.. / D1 = 5  =>  0 pairs (X) / F1 = 5  =>  0 pairs (_)
D7,E9: 5.. / D7 = 5  =>  0 pairs (X) / E9 = 5  =>  0 pairs (_)
I7,I9: 5.. / I7 = 5  =>  0 pairs (*) / I9 = 5  =>  0 pairs (X)
D7,I7: 5.. / D7 = 5  =>  0 pairs (X) / I7 = 5  =>  0 pairs (_)
E9,I9: 5.. / E9 = 5  =>  0 pairs (*) / I9 = 5  =>  0 pairs (X)
E5,E9: 5.. / E5 = 5  =>  0 pairs (X) / E9 = 5  =>  0 pairs (_)
F1,F5: 5.. / F1 = 5  =>  0 pairs (*) / F5 = 5  =>  0 pairs (X)
C1,C3: 6.. / C1 = 6  =>  0 pairs (*) / C3 = 6  =>  0 pairs (X)
G2,H3: 6.. / G2 = 6  =>  0 pairs (X) / H3 = 6  =>  0 pairs (_)
H5,G6: 6.. / H5 = 6  =>  0 pairs (X) / G6 = 6  =>  0 pairs (_)
D7,E9: 6.. / D7 = 6  =>  0 pairs (*) / E9 = 6  =>  0 pairs (X)
I7,I9: 6.. / I7 = 6  =>  0 pairs (X) / I9 = 6  =>  0 pairs (_)
E2,G2: 6.. / E2 = 6  =>  0 pairs (*) / G2 = 6  =>  0 pairs (X)
D6,G6: 6.. / D6 = 6  =>  0 pairs (X) / G6 = 6  =>  0 pairs (_)
D7,I7: 6.. / D7 = 6  =>  0 pairs (*) / I7 = 6  =>  0 pairs (X)
E9,I9: 6.. / E9 = 6  =>  0 pairs (X) / I9 = 6  =>  0 pairs (_)
F1,F5: 6.. / F1 = 6  =>  0 pairs (X) / F5 = 6  =>  0 pairs (_)
G2,G6: 6.. / G2 = 6  =>  0 pairs (X) / G6 = 6  =>  0 pairs (_)
H3,H5: 6.. / H3 = 6  =>  0 pairs (*) / H5 = 6  =>  0 pairs (X)
C1,C3: 7.. / C1 = 7  =>  0 pairs (X) / C3 = 7  =>  0 pairs (_)
I2,I3: 7.. / I2 = 7  => 16 pairs (_) / I3 = 7  =>  0 pairs (X)
D5,E5: 7.. / D5 = 7  =>  0 pairs (X) / E5 = 7  =>  0 pairs (_)
C1,D1: 7.. / C1 = 7  =>  0 pairs (X) / D1 = 7  =>  0 pairs (_)
E2,I2: 7.. / E2 = 7  =>  0 pairs (X) / I2 = 7  => 16 pairs (_)
D1,D5: 7.. / D1 = 7  =>  0 pairs (*) / D5 = 7  =>  0 pairs (X)
H3,I3: 9.. / H3 = 9  =>  0 pairs (X) / I3 = 9  => 14 pairs (_)
H8,I8: 9.. / H8 = 9  => 14 pairs (_) / I8 = 9  =>  0 pairs (X)
H3,H8: 9.. / H3 = 9  =>  0 pairs (X) / H8 = 9  => 14 pairs (_)
I3,I8: 9.. / I3 = 9  => 14 pairs (_) / I8 = 9  =>  0 pairs (X)
* DURATION: 0:01:04.003834  START: 08:23:16.109585  END: 08:24:20.113419 2017-05-04
* CP COUNT: (36)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C1,C3,D6,D7,E9,F1,F5,G2,G6,H5,H8,I2,I7,I8,I9)
* 82..9.1439413.8.5.35.4.18..268913574413...9.8579.84.31132.4978.6851374..7948.231.
* PAIR C1: 6,7 ROW 1
D1: 6,7,5                                # reduction candidate for 6,7
D1: 6,7 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
D1: 5 => CTR
* 8275961439413.865.3564.18..2689135744137.59.8579.84.31132.4978.6851374..7948.231.
* PAIR C3: 6,7 ROW 3
E3: 6,7,2                                # reduction candidate for 6,7
E3: 6,7 => CTR
* 82..9.14394132865735.4.18..268913574413...9685796842311325497866851374..794862315
E3: 2                                    # 18 pairs
* PAIR F1: 5,6 BLK 2
D1: 5,6,7                                # reduction candidate for 5,6
D1: 5,6 => CTR
* 827.9.1439413.8.5.3564.18..2689135744137..9.8579.84.31132.4978.6851374..7948.231.
D1: 7 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
* PAIR G2: 2,6 BLK 3
H3: 2,6,9                                # reduction candidate for 2,6
H3: 9 => CTR
* 82..9.1439413.865.35.4.189.268913574413...968579684231132549786685137429794862315
H3: 2,6                                  # 14 pairs
* PAIR G2: 2,6 ROW 2
E2: 2,6,7                                # reduction candidate for 2,6
E2: 7 => CTR
* 82..9.14394137865235.4218972689135744137..9.8579.84.31132.4978.6851374..7948.231.
E2: 2,6                                  # 16 pairs
* PAIR I2: 2,7 BLK 3
I3: 2,7,9                                # reduction candidate for 2,7
I3: 2,7 => CTR
* 82..9.1439413.8.5.35.4.189.268913574413...968579684231132549786685137429794862315
I3: 9                                    # 14 pairs
* PAIR I2: 2,7 ROW 2
E2: 2,7,6                                # reduction candidate for 2,7
E2: 2,7 => CTR
* 82..9.1439413.865.35.4.18..268913574413...9685796842311325497866851374..794862315
E2: 6 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
* PAIR F5: 5,6 BLK 5
D5: 5,6,2,7                              # reduction candidate for 5,6
D5: 5,6 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
D5: 2,7                                  # 16 pairs
E5: 5,6,7                                # reduction candidate for 5,6
E5: 5,6 => CTR
* 827.9.1439413682573564.18..2689135744137..928579284631132.4978.6851374927948.231.
E5: 7 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
* PAIR D6: 2,6 BLK 5
D5: 2,6,5,7                              # reduction candidate for 2,6
D5: 2,6 => CTR
* 82.7951439413.8.573574.18..268913574413...9.8579.84.31132.4978.6851374..7948.231.
D5: 5,7 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
* PAIR H5: 2,6 ROW 5
D5: 2,6,5,7                              # reduction candidate for 2,6
D5: 2,6 => CTR
* 82.7951439413.8.573574.18..268913574413...9.8579.84.31132.4978.6851374..7948.231.
D5: 5,7 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
* PAIR H5: 2,6 COL H
H3: 2,6,9                                # reduction candidate for 2,6
H3: 9 => CTR
* 82..9.1439413.865.35.4.189.268913574413...968579684231132549786685137429794862315
H3: 2,6                                  # 14 pairs
* PAIR D7: 5,6 COL D
D1: 5,6,7                                # reduction candidate for 5,6
D1: 5,6 => CTR
* 827.9.1439413.8.5.3564.18..2689135744137..9.8579.84.31132.4978.6851374..7948.231.
D1: 7 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
D5: 5,6,2,7                              # reduction candidate for 5,6
D5: 5,6 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
D5: 2,7                                  # 16 pairs
* PAIR E9: 5,6 COL E
E5: 5,6,7                                # reduction candidate for 5,6
E5: 5,6 => CTR
* 827.9.1439413682573564.18..2689135744137..928579284631132.4978.6851374927948.231.
E5: 7 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
* PAIR H8: 2,9 COL H
H3: 2,9,6                                # reduction candidate for 2,9
H3: 2,9 => CTR
* 82..9.1439413.865.35.4.18..268913574413...9685796842311325497866851374..794862315
H3: 6 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
* PAIR I8: 2,9 COL I
I3: 2,9,7                                # reduction candidate for 2,9
I3: 7 => CTR
* 82..9.1439413.8.5.35.4.1897268913574413...968579684231132549786685137429794862315
I3: 2,9                                  # 16 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-165-base-pr-000.dot
* REASONING
* PRF # D1: 6,7 => SOL
* DIS # D1: 5 => CTR => D1: 6,7
* DIS # E3: 6,7 => CTR => E3: 2
* DIS # D1: 5,6 => CTR => D1: 7
* PRF # D1: 7 => SOL
* DIS # H3: 9 => CTR => H3: 2,6
* DIS # E2: 7 => CTR => E2: 2,6
* DIS # I3: 2,7 => CTR => I3: 9
* DIS # E2: 2,7 => CTR => E2: 6
* PRF # E2: 6 => SOL
* PRF # D5: 5,6 => SOL
* DIS # E5: 5,6 => CTR => E5: 7
* PRF # E5: 7 => SOL
* DIS # D5: 2,6 => CTR => D5: 5,7
* PRF # D5: 5,7 => SOL
* DIS # D5: 2,6 => CTR => D5: 5,7
* PRF # D5: 5,7 => SOL
* DIS # H3: 9 => CTR => H3: 2,6
* DIS # D1: 5,6 => CTR => D1: 7
* PRF # D1: 7 => SOL
* PRF # D5: 5,6 => SOL
* DIS # E5: 5,6 => CTR => E5: 7
* PRF # E5: 7 => SOL
* DIS # H3: 2,9 => CTR => H3: 6
* PRF # H3: 6 => SOL
* DIS # I3: 7 => CTR => I3: 2,9
* CNT  26 HDP CHAINS /  34 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C1,C3,D6,D7,E9,F1,F5,G2,G6,H5,H8,I2,I7,I8,I9)
* 82..9.1439413.8.5.35.4.18..268913574413...9.8579.84.31132.4978.6851374..7948.231.
* PAIR C1: 6,7 ROW 1
D1: 6,7,5                                # reduction candidate for 6,7
D1: 6,7 => SOLVED
* 826795143941368257357421869268913574413576928579284631132649785685137492794852316
* DURATION: 0:00:01.978389  START: 08:24:57.127952  END: 08:24:59.106341 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-165-base-pr-001.dot
* REASONING
* PRF # D1: 6,7 => SOL
* STA D1: 6,7
* CNT   1 HDP CHAINS /   1 HYP OPENED

Header Info

Top 500 Minimum 17 165

solution: 826795143941368257357421869268913574413576928579284631132649785685137492794852316
info: 1823     FNBWY    S8.f     45375

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

Solution

position: 826795143941368257357421869268913574413576928579284631132649785685137492794852316 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 # D1: 6,7 => SOL
* DIS # D1: 5 => CTR => D1: 6,7
* DIS # E3: 6,7 => CTR => E3: 2
* INC # E3: 2 => UNS
* DIS # D1: 5,6 => CTR => D1: 7
* PRF # D1: 7 => SOL
* INC # H3: 2,6 => UNS
* DIS # H3: 9 => CTR => H3: 2,6
* INC # E2: 2,6 => UNS
* DIS # E2: 7 => CTR => E2: 2,6
* DIS # I3: 2,7 => CTR => I3: 9
* INC # I3: 9 => UNS
* DIS # E2: 2,7 => CTR => E2: 6
* PRF # E2: 6 => SOL
* PRF # D5: 5,6 => SOL
* INC # D5: 2,7 => UNS
* DIS # E5: 5,6 => CTR => E5: 7
* PRF # E5: 7 => SOL
* DIS # D5: 2,6 => CTR => D5: 5,7
* PRF # D5: 5,7 => SOL
* DIS # D5: 2,6 => CTR => D5: 5,7
* PRF # D5: 5,7 => SOL
* INC # H3: 2,6 => UNS
* DIS # H3: 9 => CTR => H3: 2,6
* DIS # D1: 5,6 => CTR => D1: 7
* PRF # D1: 7 => SOL
* PRF # D5: 5,6 => SOL
* INC # D5: 2,7 => UNS
* DIS # E5: 5,6 => CTR => E5: 7
* PRF # E5: 7 => SOL
* DIS # H3: 2,9 => CTR => H3: 6
* PRF # H3: 6 => SOL
* INC # I3: 2,9 => UNS
* DIS # I3: 7 => CTR => I3: 2,9
* CNT  34 HDP CHAINS /  34 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* PRF # D1: 6,7 => SOL
* STA D1: 6,7
* CNT   1 HDP CHAINS /   1 HYP OPENED