Analysis of xx-top500-242-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: 8......13...674............3..5..1........7.6....8.......2...8..41.......7....... initial

Autosolve

position: 867925413.136748..4..81367.3.45671.818.43.7.67.618..3463.241.87.417.836..783.6.41 autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C3: 5,9 => CTR => C3: 2
* PRF # I2: 5,9 => SOL
* PRF # A8: 5,9 => SOL
* PRF # I2: 5,9 => SOL
* DIS # C3: 5,9 => CTR => C3: 2
* PRF # I8: 2 => SOL
* DIS # B6: 2,9 => CTR => B6: 5
* DIS # B3: 5 => CTR => B3: 2,9
* DIS # H5: 2,9 => CTR => H5: 5
* DIS # B6: 2,9 => CTR => B6: 5
* DIS # H5: 2,9 => CTR => H5: 5
* DIS # H2: 5 => CTR => H2: 2,9
* PRF # A8: 5,9 => SOL
* DIS # C3: 5,9 => CTR => C3: 2
* PRF # A8: 5,9 => SOL
* PRF # G9: 5,9 => SOL
* PRF # G9: 5,9 => SOL
* PRF # G6: 2 => SOL
* CNT  18 HDP CHAINS /  50 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 # C3: 5,9 => CTR => C3: 2
* PRF C3: 2 # I2: 5,9 => SOL
* STA C3: 2 + I2: 5,9
* CNT   2 HDP CHAINS /   4 HYP OPENED

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

Details

Positions

8......13...674............3..5..1........7.6....8.......2...8..41.......7....... initial
867925413.136748..4..81367.3.45671.818.43.7.67.618..3463.241.87.417.836..783.6.41 autosolve
867925413513674829492813675324567198189432756756189234635241987941758362278396541 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (10)
A2: 5,9
I3: 5,9
B4: 2,9
F5: 2,9
F6: 2,9
H4: 2,9
C7: 5,9
E8: 5,9
E9: 5,9
G7: 5,9

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
B3,C3: 2.. / B3 = 2  =>  0 pairs (X) / C3 = 2  => 12 pairs (_)
H2,I2: 2.. / H2 = 2  =>  0 pairs (*) / I2 = 2  =>  0 pairs (X)
F5,F6: 2.. / F5 = 2  => 15 pairs (_) / F6 = 2  => 16 pairs (_)
A8,A9: 2.. / A8 = 2  => 14 pairs (_) / A9 = 2  =>  0 pairs (*)
I8,G9: 2.. / I8 = 2  =>  0 pairs (*) / G9 = 2  =>  0 pairs (X)
B4,H4: 2.. / B4 = 2  => 15 pairs (_) / H4 = 2  => 16 pairs (_)
A8,I8: 2.. / A8 = 2  => 14 pairs (_) / I8 = 2  =>  0 pairs (*)
A9,G9: 2.. / A9 = 2  =>  0 pairs (*) / G9 = 2  =>  0 pairs (X)
C3,C5: 2.. / C3 = 2  => 12 pairs (_) / C5 = 2  =>  0 pairs (X)
G6,G9: 2.. / G6 = 2  =>  0 pairs (*) / G9 = 2  =>  0 pairs (X)
I2,I8: 2.. / I2 = 2  => 14 pairs (_) / I8 = 2  =>  0 pairs (*)
C5,B6: 5.. / C5 = 5  =>  0 pairs (X) / B6 = 5  => 15 pairs (_)
H5,G6: 5.. / H5 = 5  => 15 pairs (_) / G6 = 5  =>  0 pairs (X)
E8,E9: 5.. / E8 = 5  => 16 pairs (_) / E9 = 5  => 14 pairs (_)
C5,H5: 5.. / C5 = 5  =>  0 pairs (X) / H5 = 5  => 15 pairs (_)
B6,G6: 5.. / B6 = 5  => 15 pairs (_) / G6 = 5  =>  0 pairs (X)
C7,G7: 5.. / C7 = 5  =>  0 pairs (*) / G7 = 5  =>  0 pairs (X)
B3,B6: 5.. / B3 = 5  =>  0 pairs (X) / B6 = 5  => 15 pairs (_)
H2,H5: 5.. / H2 = 5  =>  0 pairs (X) / H5 = 5  => 15 pairs (_)
F5,F6: 9.. / F5 = 9  => 16 pairs (_) / F6 = 9  => 15 pairs (_)
E8,E9: 9.. / E8 = 9  => 14 pairs (_) / E9 = 9  => 16 pairs (_)
B4,H4: 9.. / B4 = 9  => 16 pairs (_) / H4 = 9  => 15 pairs (_)
C7,G7: 9.. / C7 = 9  =>  0 pairs (X) / G7 = 9  =>  0 pairs (_)
* DURATION: 0:00:39.915415  START: 11:04:28.328554  END: 11:05:08.243969 2017-05-04
* CP COUNT: (23)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,B4,C7,E8,E9,F5,F6,G7,H4,I3)
* 867925413.136748..4..81367.3.45671.818.43.7.67.618..3463.241.87.417.836..783.6.41
* PAIR A2: 5,9 BLK 1
B3: 5,9,2                                # reduction candidate for 5,9
B3: 5,9                                  # 12 pairs
C3: 5,9,2                                # reduction candidate for 5,9
C3: 5,9 => CTR
* 867925413.136748..42.81367.394567128182439756756182934639241587.417.8369.78396241
C3: 2                                    # 12 pairs
* PAIR A2: 5,9 ROW 2
H2: 5,9,2                                # reduction candidate for 5,9
H2: 5,9                                  # 14 pairs
I2: 5,9,2                                # reduction candidate for 5,9
I2: 5,9 => SOLVED
* 867925413513674829492813675324567198189432756756189234635241987941758362278396541
I2: 2                                    # 14 pairs
* PAIR A2: 5,9 COL A
A8: 5,9,2                                # reduction candidate for 5,9
A8: 5,9 => SOLVED
* 867925413513674829492813675324567198189432756756189234635241987941758362278396541
A8: 2                                    # 14 pairs
A9: 5,9,2                                # reduction candidate for 5,9
A9: 5,9                                  # 14 pairs
* PAIR I3: 5,9 BLK 3
H2: 5,9,2                                # reduction candidate for 5,9
H2: 5,9                                  # 14 pairs
I2: 5,9,2                                # reduction candidate for 5,9
I2: 5,9 => SOLVED
* 867925413513674829492813675324567198189432756756189234635241987941758362278396541
I2: 2                                    # 14 pairs
* PAIR I3: 5,9 ROW 3
B3: 5,9,2                                # reduction candidate for 5,9
B3: 5,9                                  # 12 pairs
C3: 5,9,2                                # reduction candidate for 5,9
C3: 5,9 => CTR
* 867925413.136748..42.81367.394567128182439756756182934639241587.417.8369.78396241
C3: 2                                    # 12 pairs
* PAIR I3: 5,9 COL I
I8: 5,9,2                                # reduction candidate for 5,9
I8: 2 => SOLVED
* 867925413513674829492813675324567198189432756756189234635241987941758362278396541
I8: 5,9                                  # 14 pairs
* PAIR B4: 2,9 BLK 4
C5: 2,9,5                                # reduction candidate for 2,9
C5: 2,9                                  # 15 pairs
B6: 2,9,5                                # reduction candidate for 2,9
B6: 2,9 => CTR
* 867925413.136748..4528136793.45671.818543.7.67.618.534639241.87.417.836..783.6.41
B6: 5                                    # 15 pairs
* PAIR B4: 2,9 COL B
B3: 2,9,5                                # reduction candidate for 2,9
B3: 5 => CTR
* 867925413.136748..4528136793.45671.818543.7.67.618.534639241.87.417.836..783.6.41
B3: 2,9                                  # 15 pairs
* PAIR F5: 2,9 ROW 5
C5: 2,9,5                                # reduction candidate for 2,9
C5: 2,9                                  # 15 pairs
H5: 2,9,5                                # reduction candidate for 2,9
H5: 2,9 => CTR
* 867925413.136748524..8136793.45671.818543.7.67.618.534639241.87.417.836..783.6.41
H5: 5                                    # 15 pairs
* PAIR F6: 2,9 ROW 6
B6: 2,9,5                                # reduction candidate for 2,9
B6: 2,9 => CTR
* 867925413.136748..4528136793.45671.818543.7.67.618.534639241.87.417.836..783.6.41
B6: 5                                    # 15 pairs
G6: 2,9,5                                # reduction candidate for 2,9
G6: 2,9                                  # 15 pairs
* PAIR H4: 2,9 BLK 6
H5: 2,9,5                                # reduction candidate for 2,9
H5: 2,9 => CTR
* 867925413.136748524..8136793.45671.818543.7.67.618.534639241.87.417.836..783.6.41
H5: 5                                    # 15 pairs
G6: 2,9,5                                # reduction candidate for 2,9
G6: 2,9                                  # 15 pairs
* PAIR H4: 2,9 COL H
H2: 2,9,5                                # reduction candidate for 2,9
H2: 5 => CTR
* 867925413.136748524..8136793.45671.818543.7.67.618.534639241.87.417.836..783.6.41
H2: 2,9                                  # 15 pairs
* PAIR C7: 5,9 BLK 7
A8: 5,9,2                                # reduction candidate for 5,9
A8: 5,9 => SOLVED
* 867925413513674829492813675324567198189432756756189234635241987941758362278396541
A8: 2                                    # 14 pairs
A9: 5,9,2                                # reduction candidate for 5,9
A9: 5,9                                  # 14 pairs
* PAIR C7: 5,9 COL C
C3: 5,9,2                                # reduction candidate for 5,9
C3: 5,9 => CTR
* 867925413.136748..42.81367.394567128182439756756182934639241587.417.8369.78396241
C3: 2                                    # 12 pairs
C5: 5,9,2                                # reduction candidate for 5,9
C5: 5,9                                  # 12 pairs
* PAIR E8: 5,9 ROW 8
A8: 5,9,2                                # reduction candidate for 5,9
A8: 5,9 => SOLVED
* 867925413513674829492813675324567198189432756756189234635241987941758362278396541
A8: 2                                    # 14 pairs
I8: 5,9,2                                # reduction candidate for 5,9
I8: 5,9                                  # 14 pairs
* PAIR E9: 5,9 ROW 9
A9: 5,9,2                                # reduction candidate for 5,9
A9: 5,9                                  # 14 pairs
G9: 5,9,2                                # reduction candidate for 5,9
G9: 5,9 => SOLVED
* 867925413513674829492813675324567198189432756756189234635241987941758362278396541
G9: 2                                    # 14 pairs
* PAIR G7: 5,9 BLK 9
I8: 5,9,2                                # reduction candidate for 5,9
I8: 5,9                                  # 14 pairs
G9: 5,9,2                                # reduction candidate for 5,9
G9: 5,9 => SOLVED
* 867925413513674829492813675324567198189432756756189234635241987941758362278396541
G9: 2                                    # 14 pairs
* PAIR G7: 5,9 COL G
G6: 5,9,2                                # reduction candidate for 5,9
G6: 2 => SOLVED
* 867925413513674829492813675324567198189432756756189234635241987941758362278396541
G6: 5,9                                  # 14 pairs
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-242-base-pr-000.dot
* REASONING
* DIS # C3: 5,9 => CTR => C3: 2
* PRF # I2: 5,9 => SOL
* PRF # A8: 5,9 => SOL
* PRF # I2: 5,9 => SOL
* DIS # C3: 5,9 => CTR => C3: 2
* PRF # I8: 2 => SOL
* DIS # B6: 2,9 => CTR => B6: 5
* DIS # B3: 5 => CTR => B3: 2,9
* DIS # H5: 2,9 => CTR => H5: 5
* DIS # B6: 2,9 => CTR => B6: 5
* DIS # H5: 2,9 => CTR => H5: 5
* DIS # H2: 5 => CTR => H2: 2,9
* PRF # A8: 5,9 => SOL
* DIS # C3: 5,9 => CTR => C3: 2
* PRF # A8: 5,9 => SOL
* PRF # G9: 5,9 => SOL
* PRF # G9: 5,9 => SOL
* PRF # G6: 2 => SOL
* CNT  18 HDP CHAINS /  50 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A2,B4,C7,E8,E9,F5,F6,G7,H4,I3)
* 867925413.136748..4..81367.3.45671.818.43.7.67.618..3463.241.87.417.836..783.6.41
* PAIR A2: 5,9 BLK 1
B3: 5,9,2                                # reduction candidate for 5,9
B3: 5,9                                  # 12 pairs
C3: 5,9,2                                # reduction candidate for 5,9
C3: 5,9 => CTR
* 867925413.136748..42.81367.394567128182439756756182934639241587.417.8369.78396241
* RESTART
* PAIR A2: 5,9 ROW 2
H2: 5,9,2                                # reduction candidate for 5,9
H2: 5,9                                  # 16 pairs
I2: 5,9,2                                # reduction candidate for 5,9
I2: 5,9 => SOLVED
* 867925413513674829492813675324567198189432756756189234635241987941758362278396541
* DURATION: 0:00:04.907793  START: 11:05:58.791854  END: 11:06:03.699647 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-242-base-pr-001.dot
* REASONING
* DIS # C3: 5,9 => CTR => C3: 2
* PRF C3: 2 # I2: 5,9 => SOL
* STA C3: 2 + I2: 5,9
* CNT   2 HDP CHAINS /   4 HYP OPENED

Header Info

Top 500 Minimum 17 242

solution: 867925413513674829492813675324567198189432756756189234635241987941758362278396541
info: 2069     FNBWX    S8.f     37857

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

Solution

position: 867925413513674829492813675324567198189432756756189234635241987941758362278396541 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 # B3: 5,9 => UNS
* DIS # C3: 5,9 => CTR => C3: 2
* INC # C3: 2 => UNS
* INC # H2: 5,9 => UNS
* PRF # I2: 5,9 => SOL
* INC # I2: 2 => UNS
* PRF # A8: 5,9 => SOL
* INC # A8: 2 => UNS
* INC # A9: 5,9 => UNS
* INC # H2: 5,9 => UNS
* PRF # I2: 5,9 => SOL
* INC # I2: 2 => UNS
* INC # B3: 5,9 => UNS
* DIS # C3: 5,9 => CTR => C3: 2
* INC # C3: 2 => UNS
* INC # I8: 5,9 => UNS
* PRF # I8: 2 => SOL
* INC # C5: 2,9 => UNS
* DIS # B6: 2,9 => CTR => B6: 5
* INC # B6: 5 => UNS
* INC # B3: 2,9 => UNS
* DIS # B3: 5 => CTR => B3: 2,9
* INC # C5: 2,9 => UNS
* DIS # H5: 2,9 => CTR => H5: 5
* INC # H5: 5 => UNS
* DIS # B6: 2,9 => CTR => B6: 5
* INC # B6: 5 => UNS
* INC # G6: 2,9 => UNS
* DIS # H5: 2,9 => CTR => H5: 5
* INC # H5: 5 => UNS
* INC # G6: 2,9 => UNS
* INC # H2: 2,9 => UNS
* DIS # H2: 5 => CTR => H2: 2,9
* PRF # A8: 5,9 => SOL
* INC # A8: 2 => UNS
* INC # A9: 5,9 => UNS
* DIS # C3: 5,9 => CTR => C3: 2
* INC # C3: 2 => UNS
* INC # C5: 5,9 => UNS
* PRF # A8: 5,9 => SOL
* INC # A8: 2 => UNS
* INC # I8: 5,9 => UNS
* INC # A9: 5,9 => UNS
* PRF # G9: 5,9 => SOL
* INC # G9: 2 => UNS
* INC # I8: 5,9 => UNS
* PRF # G9: 5,9 => SOL
* INC # G9: 2 => UNS
* INC # G6: 5,9 => UNS
* PRF # G6: 2 => SOL
* CNT  50 HDP CHAINS /  50 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # B3: 5,9 => UNS
* DIS # C3: 5,9 => CTR => C3: 2
* INC C3: 2 # H2: 5,9 => UNS
* PRF C3: 2 # I2: 5,9 => SOL
* STA C3: 2 + I2: 5,9
* CNT   4 HDP CHAINS /   4 HYP OPENED