Analysis of xx-top500-245-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ....8.32.1.4..9.............3..2....7.......1.......5....1.7..9.2....7.....4..... initial

Autosolve

position: .7..813241.4239...2.3.7419.5319264..7928456318467139523.81.724942.3.871..174.2..3 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # B3: 5,6 => CTR => B3: 8
* DIS # I2: 5,8 => CTR => I2: 6,7
* DIS # B2: 6 => CTR => B2: 5,8
* DIS # H2: 7,8 => CTR => H2: 6
* PRF # H2: 6 => SOL
* DIS # I2: 5,6 => CTR => I2: 7,8
* DIS # B3: 5,6 => CTR => B3: 8
* PRF # E8: 5,9 => SOL
* DIS # E8: 6 => CTR => E8: 5,9
* PRF # E9: 6,9 => SOL
* DIS # E9: 5 => CTR => E9: 6,9
* DIS # E8: 5,6 => CTR => E8: 9
* PRF # E8: 9 => SOL
* PRF # E9: 5,6 => SOL
* DIS # E9: 9 => CTR => E9: 5,6
* DIS # E8: 5,6 => CTR => E8: 9
* PRF # E8: 9 => SOL
* DIS # I2: 5,6 => CTR => I2: 7,8
* DIS # H2: 7 => CTR => H2: 6,8
* CNT  19 HDP CHAINS /  30 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 # B3: 5,6 => CTR => B3: 8
* DIS B3: 8 # H2: 7,8 => CTR => H2: 6
* PRF B3: 8 + H2: 6 => SOL
* STA B3: 8 + H2: 6
* CNT   3 HDP CHAINS /   2 HYP OPENED

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

Details

Positions

....8.32.1.4..9.............3..2....7.......1.......5....1.7..9.2....7.....4..... initial
.7..813241.4239...2.3.7419.5319264..7928456318467139523.81.724942.3.871..174.2..3 autosolve
679581324154239867283674195531926478792845631846713952368157249425398716917462583 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (14)
A1: 6,9
C1: 5,9
D1: 5,6
D3: 5,6
G2: 5,8
H4: 7,8
I4: 7,8
B7: 5,6
C8: 5,9
A9: 6,9
E7: 5,6
I8: 5,6
G9: 5,8
H9: 6,8

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
D1,D3: 5.. / D1 = 5  =>  0 pairs (*) / D3 = 5  =>  0 pairs (X)
B7,C8: 5.. / B7 = 5  =>  0 pairs (X) / C8 = 5  =>  0 pairs (_)
I8,G9: 5.. / I8 = 5  =>  0 pairs (X) / G9 = 5  =>  0 pairs (_)
C1,D1: 5.. / C1 = 5  =>  0 pairs (X) / D1 = 5  =>  0 pairs (_)
B7,E7: 5.. / B7 = 5  =>  0 pairs (X) / E7 = 5  =>  0 pairs (_)
E9,G9: 5.. / E9 = 5  =>  0 pairs (X) / G9 = 5  =>  0 pairs (_)
C1,C8: 5.. / C1 = 5  =>  0 pairs (X) / C8 = 5  =>  0 pairs (_)
G2,G9: 5.. / G2 = 5  =>  0 pairs (X) / G9 = 5  =>  0 pairs (_)
D1,D3: 6.. / D1 = 6  =>  0 pairs (X) / D3 = 6  =>  0 pairs (_)
B7,A9: 6.. / B7 = 6  =>  0 pairs (*) / A9 = 6  =>  0 pairs (X)
I8,H9: 6.. / I8 = 6  =>  0 pairs (*) / H9 = 6  =>  0 pairs (X)
A1,D1: 6.. / A1 = 6  =>  0 pairs (*) / D1 = 6  =>  0 pairs (X)
B7,E7: 6.. / B7 = 6  =>  0 pairs (*) / E7 = 6  =>  0 pairs (X)
E8,I8: 6.. / E8 = 6  =>  0 pairs (X) / I8 = 6  =>  0 pairs (_)
A1,A9: 6.. / A1 = 6  =>  0 pairs (*) / A9 = 6  =>  0 pairs (X)
H2,H9: 6.. / H2 = 6  =>  0 pairs (*) / H9 = 6  =>  0 pairs (X)
H2,I2: 7.. / H2 = 7  =>  0 pairs (X) / I2 = 7  => 15 pairs (_)
H4,I4: 7.. / H4 = 7  => 15 pairs (_) / I4 = 7  =>  0 pairs (X)
H2,H4: 7.. / H2 = 7  =>  0 pairs (X) / H4 = 7  => 15 pairs (_)
I2,I4: 7.. / I2 = 7  => 15 pairs (_) / I4 = 7  =>  0 pairs (X)
B2,B3: 8.. / B2 = 8  =>  0 pairs (X) / B3 = 8  => 17 pairs (_)
H4,I4: 8.. / H4 = 8  =>  0 pairs (X) / I4 = 8  => 15 pairs (_)
G9,H9: 8.. / G9 = 8  =>  0 pairs (X) / H9 = 8  =>  0 pairs (_)
B3,I3: 8.. / B3 = 8  => 17 pairs (_) / I3 = 8  =>  0 pairs (X)
G2,G9: 8.. / G2 = 8  =>  0 pairs (*) / G9 = 8  =>  0 pairs (X)
A1,C1: 9.. / A1 = 9  =>  0 pairs (X) / C1 = 9  =>  0 pairs (_)
C8,A9: 9.. / C8 = 9  =>  0 pairs (X) / A9 = 9  =>  0 pairs (_)
E8,E9: 9.. / E8 = 9  =>  0 pairs (*) / E9 = 9  =>  0 pairs (X)
C8,E8: 9.. / C8 = 9  =>  0 pairs (X) / E8 = 9  =>  0 pairs (_)
A9,E9: 9.. / A9 = 9  =>  0 pairs (*) / E9 = 9  =>  0 pairs (X)
A1,A9: 9.. / A1 = 9  =>  0 pairs (X) / A9 = 9  =>  0 pairs (_)
C1,C8: 9.. / C1 = 9  =>  0 pairs (*) / C8 = 9  =>  0 pairs (X)
* DURATION: 0:00:56.017730  START: 11:10:21.680671  END: 11:11:17.698401 2017-05-04
* CP COUNT: (32)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A9,B7,C1,C8,D1,D3,E7,G2,G9,H4,H9,I4,I8)
* .7..813241.4239...2.3.7419.5319264..7928456318467139523.81.724942.3.871..174.2..3
* PAIR D3: 5,6 ROW 3
B3: 5,6,8                                # reduction candidate for 5,6
B3: 5,6 => CTR
* .7..813241842395..2.3.741985319264877928456318467139523.81.724942.3.8715.17452863
B3: 8                                    # 17 pairs
I3: 5,6,8                                # reduction candidate for 5,6
I3: 5,6                                  # 17 pairs
* PAIR G2: 5,8 BLK 3
I2: 5,8,6,7                              # reduction candidate for 5,8
I2: 5,8 => CTR
* .7..813241.4239.7.2.3.741965319264877928456318467139523.81.724942.368715.174.2..3
I2: 6,7                                  # 15 pairs
I3: 5,8,6                                # reduction candidate for 5,8
I3: 5,8                                  # 18 pairs
* PAIR G2: 5,8 ROW 2
B2: 5,8,6                                # reduction candidate for 5,8
B2: 6 => CTR
* .7..81324164239...283.741965319264..79284563184671395235816724942935871..174.2..3
B2: 5,8                                  # 18 pairs
* PAIR H4: 7,8 COL H
H2: 7,8,6                                # reduction candidate for 7,8
H2: 7,8 => CTR
* 6795813241.4239..62.367419.5319264.779284563184671395236815724942.3.871..174.2.63
H2: 6 => SOLVED
* 679581324154239867283674195531926478792845631846713952368157249425398716917462583
* PAIR I4: 7,8 COL I
I2: 7,8,5,6                              # reduction candidate for 7,8
I2: 5,6 => CTR
* 67958132418423957625367419853192648779284563184671395236815724942.3.871..174.2863
I2: 7,8                                  # 17 pairs
* PAIR B7: 5,6 COL B
B2: 5,6,8                                # reduction candidate for 5,6
B2: 5,6                                  # 17 pairs
B3: 5,6,8                                # reduction candidate for 5,6
B3: 5,6 => CTR
* .7..813241842395..2.3.741985319264877928456318467139523.81.724942.3.8715.17452863
B3: 8                                    # 17 pairs
* PAIR C8: 5,9 ROW 8
E8: 5,9,6                                # reduction candidate for 5,9
E8: 5,9 => SOLVED
* 679581324154239867283674195531926478792845631846713952368157249425398716917462583
E8: 6 => CTR
* .7..813241.4239...2.3.7419.5319264..7928456318467139523.81.72494293687156174.2..3
* PAIR A9: 6,9 ROW 9
E9: 6,9,5                                # reduction candidate for 6,9
E9: 6,9 => SOLVED
* 679581324154239867283674195531926478792845631846713952368157249425398716917462583
E9: 5 => CTR
* .7..813241.4239...2.3.7419.5319264..7928456318467139523.81.724942.398716.174.2..3
* PAIR E7: 5,6 BLK 8
E8: 5,6,9                                # reduction candidate for 5,6
E8: 5,6 => CTR
* 9756813241.423986.2.3.7419.5319264..7928456318467139523.81.72494293.871.617492583
E8: 9 => SOLVED
* 679581324154239867283674195531926478792845631846713952368157249425398716917462583
E9: 5,6,9                                # reduction candidate for 5,6
E9: 5,6 => SOLVED
* 679581324154239867283674195531926478792845631846713952368157249425398716917462583
E9: 9 => CTR
* 9756813241.423986.2.3.7419.5319264..7928456318467139523.81.724942.3.871..17492583
* PAIR I8: 5,6 ROW 8
E8: 5,6,9                                # reduction candidate for 5,6
E8: 5,6 => CTR
* 9756813241.423986.2.3.7419.5319264..7928456318467139523.81.72494293.871.617492583
E8: 9 => SOLVED
* 679581324154239867283674195531926478792845631846713952368157249425398716917462583
* PAIR I8: 5,6 COL I
I2: 5,6,7,8                              # reduction candidate for 5,6
I2: 5,6 => CTR
* 67958132418423957625367419853192648779284563184671395236815724942.3.871..174.2863
I2: 7,8                                  # 17 pairs
I3: 5,6,8                                # reduction candidate for 5,6
I3: 5,6                                  # 17 pairs
* PAIR H9: 6,8 COL H
H2: 6,8,7                                # reduction candidate for 6,8
H2: 7 => CTR
* 6795813241.423957625367419853192648779284563184671395236815724942.3.871..174.2863
H2: 6,8                                  # 15 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-245-base-pr-000.dot
* REASONING
* DIS # B3: 5,6 => CTR => B3: 8
* DIS # I2: 5,8 => CTR => I2: 6,7
* DIS # B2: 6 => CTR => B2: 5,8
* DIS # H2: 7,8 => CTR => H2: 6
* PRF # H2: 6 => SOL
* DIS # I2: 5,6 => CTR => I2: 7,8
* DIS # B3: 5,6 => CTR => B3: 8
* PRF # E8: 5,9 => SOL
* DIS # E8: 6 => CTR => E8: 5,9
* PRF # E9: 6,9 => SOL
* DIS # E9: 5 => CTR => E9: 6,9
* DIS # E8: 5,6 => CTR => E8: 9
* PRF # E8: 9 => SOL
* PRF # E9: 5,6 => SOL
* DIS # E9: 9 => CTR => E9: 5,6
* DIS # E8: 5,6 => CTR => E8: 9
* PRF # E8: 9 => SOL
* DIS # I2: 5,6 => CTR => I2: 7,8
* DIS # H2: 7 => CTR => H2: 6,8
* CNT  19 HDP CHAINS /  30 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A1,A9,B7,C1,C8,D1,D3,E7,G2,G9,H4,H9,I4,I8)
* .7..813241.4239...2.3.7419.5319264..7928456318467139523.81.724942.3.871..174.2..3
* PAIR D3: 5,6 ROW 3
B3: 5,6,8                                # reduction candidate for 5,6
B3: 5,6 => CTR
* .7..813241842395..2.3.741985319264877928456318467139523.81.724942.3.8715.17452863
* RESTART
* PAIR RESTART
* PAIR H4: 7,8 COL H
H2: 7,8,6                                # reduction candidate for 7,8
H2: 7,8 => CTR
* .7..813241642395..2835741965319264..79284563184671395235816724942935871..174.2..3
H2: 6 => SOLVED
* 679581324154239867283674195531926478792845631846713952368157249425398716917462583
* DURATION: 0:00:04.223617  START: 11:11:48.982572  END: 11:11:53.206189 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-245-base-pr-001.dot
* REASONING
* DIS # B3: 5,6 => CTR => B3: 8
* DIS B3: 8 # H2: 7,8 => CTR => H2: 6
* PRF B3: 8 + H2: 6 => SOL
* STA B3: 8 + H2: 6
* CNT   3 HDP CHAINS /   2 HYP OPENED

Header Info

Top 500 Minimum 17 245

solution: 679581324154239867283674195531926478792845631846713952368157249425398716917462583
info: 2071     FNBTWXY  S8.f     6236

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

Solution

position: 679581324154239867283674195531926478792845631846713952368157249425398716917462583 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 # B3: 5,6 => CTR => B3: 8
* INC # B3: 8 => UNS
* INC # I3: 5,6 => UNS
* DIS # I2: 5,8 => CTR => I2: 6,7
* INC # I2: 6,7 => UNS
* INC # I3: 5,8 => UNS
* INC # B2: 5,8 => UNS
* DIS # B2: 6 => CTR => B2: 5,8
* DIS # H2: 7,8 => CTR => H2: 6
* PRF # H2: 6 => SOL
* INC # I2: 7,8 => UNS
* DIS # I2: 5,6 => CTR => I2: 7,8
* INC # B2: 5,6 => UNS
* DIS # B3: 5,6 => CTR => B3: 8
* INC # B3: 8 => UNS
* PRF # E8: 5,9 => SOL
* DIS # E8: 6 => CTR => E8: 5,9
* PRF # E9: 6,9 => SOL
* DIS # E9: 5 => CTR => E9: 6,9
* DIS # E8: 5,6 => CTR => E8: 9
* PRF # E8: 9 => SOL
* PRF # E9: 5,6 => SOL
* DIS # E9: 9 => CTR => E9: 5,6
* DIS # E8: 5,6 => CTR => E8: 9
* PRF # E8: 9 => SOL
* DIS # I2: 5,6 => CTR => I2: 7,8
* INC # I2: 7,8 => UNS
* INC # I3: 5,6 => UNS
* INC # H2: 6,8 => UNS
* DIS # H2: 7 => CTR => H2: 6,8
* CNT  30 HDP CHAINS /  30 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* DIS # B3: 5,6 => CTR => B3: 8
* DIS B3: 8 # H2: 7,8 => CTR => H2: 6
* PRF B3: 8 + H2: 6 => SOL
* STA B3: 8 + H2: 6
* CNT   3 HDP CHAINS /   2 HYP OPENED