Analysis of xx-top500-407-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: .2..5.64.31...........8.......62....8......7.........1...3.7.....9...2.....1..... initial

Autosolve

position: 72895164331..76.......83......62....8..51..7....73...1...3.7.....98.52.....1.2... autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # C4: 4,5 => CTR => C4: 1,3,7
* DIS # C7: 4,5 => CTR => C7: 1,2,6
* DIS # C9: 4,5 => CTR => C9: 3,6,7
* DIS # B5: 4,9 => CTR => B5: 3,6
* DIS # C5: 2,6 => CTR => C5: 3,4
* DIS # A8: 4,6 => CTR => A8: 1
* PRF # A8: 1 => SOL
* PRF # B8: 4,6 => SOL
* DIS # I8: 4,6 => CTR => I8: 7
* PRF # I8: 7 => SOL
* CNT  10 HDP CHAINS /  27 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 # C4: 4,5 => CTR => C4: 1,3,7
* DIS C4: 1,3,7 # C7: 4,5 => CTR => C7: 1,2,6
* DIS C4: 1,3,7 + C7: 1,2,6 # C9: 4,5 => CTR => C9: 3,6,7
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # B5: 4,9 => CTR => B5: 3,6
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 # G5: 3 => CTR => G5: 4,9
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 # C5: 2,6 => CTR => C5: 3
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 + C5: 3 # A8: 4,6 => CTR => A8: 1
* PRF C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 + C5: 3 + A8: 1 => SOL
* STA C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 + C5: 3 + A8: 1
* CNT   8 HDP CHAINS /  26 HYP OPENED

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

Details

Positions

.2..5.64.31...........8.......62....8......7.........1...3.7.....9...2.....1..... initial
72895164331..76.......83......62....8..51..7....73...1...3.7.....98.52.....1.2... autosolve
728951643315476829496283715971624358863519472254738961582347196149865237637192584 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (7)
C2: 4,5
D2: 2,4
D3: 2,4
F5: 4,9
I5: 2,6
H6: 2,6
E8: 4,6

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
G3,H3: 1.. / G3 = 1  =>  0 pairs (X) / H3 = 1  =>  0 pairs (_)
A4,C4: 1.. / A4 = 1  =>  0 pairs (X) / C4 = 1  =>  0 pairs (_)
A8,H8: 1.. / A8 = 1  =>  0 pairs (*) / H8 = 1  =>  0 pairs (X)
C4,C7: 1.. / C4 = 1  =>  0 pairs (*) / C7 = 1  =>  0 pairs (X)
G3,G7: 1.. / G3 = 1  =>  0 pairs (X) / G7 = 1  =>  0 pairs (_)
D2,D3: 2.. / D2 = 2  =>  8 pairs (_) / D3 = 2  =>  8 pairs (_)
I5,H6: 2.. / I5 = 2  =>  7 pairs (_) / H6 = 2  =>  0 pairs (X)
A7,C7: 2.. / A7 = 2  =>  7 pairs (_) / C7 = 2  =>  0 pairs (*)
C5,I5: 2.. / C5 = 2  =>  0 pairs (X) / I5 = 2  =>  7 pairs (_)
A6,A7: 2.. / A6 = 2  =>  0 pairs (*) / A7 = 2  =>  0 pairs (X)
B8,H8: 3.. / B8 = 3  =>  0 pairs (X) / H8 = 3  =>  0 pairs (_)
D2,D3: 4.. / D2 = 4  =>  8 pairs (_) / D3 = 4  =>  8 pairs (_)
C2,D2: 4.. / C2 = 4  =>  8 pairs (_) / D2 = 4  =>  8 pairs (_)
I5,H6: 6.. / I5 = 6  =>  0 pairs (X) / H6 = 6  =>  7 pairs (_)
G3,I3: 7.. / G3 = 7  =>  0 pairs (*) / I3 = 7  =>  0 pairs (X)
B4,C4: 7.. / B4 = 7  =>  0 pairs (*) / C4 = 7  =>  0 pairs (X)
B8,I8: 7.. / B8 = 7  =>  0 pairs (X) / I8 = 7  =>  0 pairs (_)
C4,C9: 7.. / C4 = 7  =>  0 pairs (X) / C9 = 7  =>  0 pairs (_)
G3,G9: 7.. / G3 = 7  =>  0 pairs (*) / G9 = 7  =>  0 pairs (X)
F4,F6: 8.. / F4 = 8  =>  9 pairs (_) / F6 = 8  =>  8 pairs (_)
B7,B9: 8.. / B7 = 8  =>  7 pairs (_) / B9 = 8  =>  9 pairs (_)
F6,G6: 8.. / F6 = 8  =>  8 pairs (_) / G6 = 8  =>  9 pairs (_)
A3,B3: 9.. / A3 = 9  =>  7 pairs (_) / B3 = 9  =>  7 pairs (_)
E7,E9: 9.. / E7 = 9  =>  8 pairs (_) / E9 = 9  =>  8 pairs (_)
* DURATION: 0:00:34.788505  START: 16:44:58.738417  END: 16:45:33.526922 2017-05-04
* CP COUNT: (24)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C2,D2,D3,E8,F5,H6,I5)
* 72895164331..76.......83......62....8..51..7....73...1...3.7.....98.52.....1.2...
* PAIR C2: 4,5 BLK 1
A3: 4,5,6,9                              # reduction candidate for 4,5
A3: 4,5                                  #  8 pairs
B3: 4,5,6,9                              # reduction candidate for 4,5
B3: 4,5                                  #  8 pairs
C3: 4,5,6                                # reduction candidate for 4,5
C3: 4,5                                  # 12 pairs
* PAIR C2: 4,5 COL C
C4: 4,5,1,3,7                            # reduction candidate for 4,5
C4: 4,5 => CTR
* 72895164331..76.......83...17.62....8..51..7....73...1..13.7.....98.5217..71.2...
C4: 1,3,7                                #  7 pairs
C6: 4,5,2,6                              # reduction candidate for 4,5
C6: 4,5                                  # 11 pairs
C7: 4,5,1,2,6                            # reduction candidate for 4,5
C7: 4,5 => CTR
* 72895164331..76.2...6283715.7162.3..86351..72..273..6128.3.71..1498652376371.2...
C7: 1,2,6                                #  7 pairs
C9: 4,5,3,6,7                            # reduction candidate for 4,5
C9: 4,5 => CTR
* 72895164331..76.....6.831.71.762....86351..72...73..61..13.7.....98.521....1.2...
C9: 3,6,7                                #  7 pairs
* PAIR F5: 4,9 BLK 5
F4: 4,9,8                                # reduction candidate for 4,9
F4: 4,9                                  #  8 pairs
F6: 4,9,8                                # reduction candidate for 4,9
F6: 4,9                                  #  9 pairs
* PAIR F5: 4,9 ROW 5
B5: 4,9,3,6                              # reduction candidate for 4,9
B5: 4,9 => CTR
* 72895164331..76.......831.71.362....8..51.37....73...12.13.7.....98.521....1.2.3.
B5: 3,6                                  #  8 pairs
G5: 4,9,3                                # reduction candidate for 4,9
G5: 4,9                                  #  9 pairs
* PAIR I5: 2,6 ROW 5
C5: 2,6,3,4                              # reduction candidate for 2,6
C5: 2,6 => CTR
* 72895164331..76.......831.71..62....8..51..7....73...12.13.7.....98.521....1.2...
C5: 3,4                                  #  8 pairs
* PAIR H6: 2,6 ROW 6
A6: 2,6,4,5,9                            # reduction candidate for 2,6
A6: 2,6                                  # 12 pairs
C6: 2,6,4,5                              # reduction candidate for 2,6
C6: 2,6                                  #  8 pairs
* PAIR E8: 4,6 BLK 8
E7: 4,6,9                                # reduction candidate for 4,6
E7: 4,6                                  #  8 pairs
E9: 4,6,9                                # reduction candidate for 4,6
E9: 4,6                                  #  8 pairs
* PAIR E8: 4,6 ROW 8
A8: 4,6,1                                # reduction candidate for 4,6
A8: 4,6 => CTR
* 72895164331..76.......831.7...62....8..51..7....73...1...3.7.....98.521....1.2...
A8: 1 => SOLVED
* 728951643315476829496283715971624358863519472254738961582347196149865237637192584
B8: 4,6,3,7                              # reduction candidate for 4,6
B8: 4,6 => SOLVED
* 728951643315476829496283715971624358863519472254738961582347196149865237637192584
B8: 3,7                                  #  8 pairs
I8: 4,6,7                                # reduction candidate for 4,6
I8: 4,6 => CTR
* 72895164331..76.......83.....762....8..51..7....73...1..13.7....798.523....1.2...
I8: 7 => SOLVED
* 728951643315476829496283715971624358863519472254738961582347196149865237637192584
* INCONCLUSIVE
* SAVE PR GRAPH xx-top500-407-base-pr-000.dot
* REASONING
* DIS # C4: 4,5 => CTR => C4: 1,3,7
* DIS # C7: 4,5 => CTR => C7: 1,2,6
* DIS # C9: 4,5 => CTR => C9: 3,6,7
* DIS # B5: 4,9 => CTR => B5: 3,6
* DIS # C5: 2,6 => CTR => C5: 3,4
* DIS # A8: 4,6 => CTR => A8: 1
* PRF # A8: 1 => SOL
* PRF # B8: 4,6 => SOL
* DIS # I8: 4,6 => CTR => I8: 7
* PRF # I8: 7 => SOL
* CNT  10 HDP CHAINS /  27 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (C2,D2,D3,E8,F5,H6,I5)
* 72895164331..76.......83......62....8..51..7....73...1...3.7.....98.52.....1.2...
* PAIR C2: 4,5 BLK 1
A3: 4,5,6,9                              # reduction candidate for 4,5
A3: 4,5                                  #  8 pairs
B3: 4,5,6,9                              # reduction candidate for 4,5
B3: 4,5                                  #  8 pairs
C3: 4,5,6                                # reduction candidate for 4,5
C3: 4,5                                  # 12 pairs
* PAIR C2: 4,5 COL C
C4: 4,5,1,3,7                            # reduction candidate for 4,5
C4: 4,5 => CTR
* 72895164331..76.......83...17.62....8..51..7....73...1..13.7.....98.5217..71.2...
C6: 4,5,2,6                              # reduction candidate for 4,5
C6: 4,5                                  # 11 pairs
C7: 4,5,1,2,6                            # reduction candidate for 4,5
C7: 4,5 => CTR
* 72895164331..76.2...6283715.7162.3..86351..72..273..6128.3.71..1498652376371.2...
C9: 4,5,3,6,7                            # reduction candidate for 4,5
C9: 4,5 => CTR
* 72895164331..76.....6.831.71.762....86351..72...73..61..13.7.....98.521....1.2...
* RESTART
* PAIR C2: 4,5 COL C
C6: 4,5,2,6                              # reduction candidate for 4,5
C6: 4,5                                  # 11 pairs
C6: 2,6                                  #  9 pairs
* PAIR RESTART
* PAIR C2: 4,5 BLK 1
A3: 4,5,6,9                              # reduction candidate for 4,5
A3: 4,5                                  # 10 pairs
B3: 4,5,6,9                              # reduction candidate for 4,5
B3: 4,5                                  # 10 pairs
C3: 4,5,6                                # reduction candidate for 4,5
C3: 4,5                                  # 12 pairs
* PAIR C2: 4,5 COL C
C6: 4,5,2,6                              # reduction candidate for 4,5
C6: 4,5                                  # 11 pairs
C6: 2,6                                  #  9 pairs
* PAIR F5: 4,9 BLK 5
F4: 4,9,8                                # reduction candidate for 4,9
F4: 4,9                                  #  8 pairs
F6: 4,9,8                                # reduction candidate for 4,9
F6: 4,9                                  #  9 pairs
* PAIR F5: 4,9 ROW 5
B5: 4,9,3,6                              # reduction candidate for 4,9
B5: 4,9 => CTR
* 72895164331..76.......831.71.362....8..51.37....73...12.13.7.....98.521....1.2.3.
G5: 4,9,3                                # reduction candidate for 4,9
G5: 4,9                                  # 10 pairs
* RESTART
* PAIR F5: 4,9 ROW 5
G5: 4,9,3                                # reduction candidate for 4,9
G5: 3 => CTR
* 728951643315476.2...62831571.362....864519372..273..612.13.7.....98.521....1.2.3.
* PAIR RESTART
* PAIR F5: 4,9 BLK 5
F4: 4,9,8                                # reduction candidate for 4,9
F4: 4,9                                  # 11 pairs
F6: 4,9,8                                # reduction candidate for 4,9
F6: 4,9                                  # 12 pairs
* PAIR I5: 2,6 ROW 5
C5: 2,6,3                                # reduction candidate for 2,6
C5: 2,6 => CTR
* 72895164331..76.......83.....762.3..83.51..7....73...1..13.7.....98.523...31.2...
* PAIR RESTART
* PAIR E8: 4,6 BLK 8
E7: 4,6,9                                # reduction candidate for 4,6
E7: 4,6                                  # 11 pairs
E9: 4,6,9                                # reduction candidate for 4,6
E9: 4,6                                  # 11 pairs
* PAIR E8: 4,6 ROW 8
A8: 4,6,1                                # reduction candidate for 4,6
A8: 4,6 => CTR
* 72895164331..76.......831.7...62....86351..72...73..61...3.7.....98.521....1.2...
A8: 1 => SOLVED
* 728951643315476829496283715971624358863519472254738961582347196149865237637192584
* DURATION: 0:00:21.310525  START: 16:45:54.180853  END: 16:46:15.491378 2017-05-04
* SOLUTION FOUND
* SAVE PR GRAPH xx-top500-407-base-pr-001.dot
* REASONING
* DIS # C4: 4,5 => CTR => C4: 1,3,7
* DIS C4: 1,3,7 # C7: 4,5 => CTR => C7: 1,2,6
* DIS C4: 1,3,7 + C7: 1,2,6 # C9: 4,5 => CTR => C9: 3,6,7
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # B5: 4,9 => CTR => B5: 3,6
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 # G5: 3 => CTR => G5: 4,9
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 # C5: 2,6 => CTR => C5: 3
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 + C5: 3 # A8: 4,6 => CTR => A8: 1
* PRF C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 + C5: 3 + A8: 1 => SOL
* STA C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 + C5: 3 + A8: 1
* CNT   8 HDP CHAINS /  26 HYP OPENED

Header Info

Top 500 Minimum 17 407

solution: 728951643315476829496283715971624358863519472254738961582347196149865237637192584
info: 94836    FNBHYK   S8.f     48427

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

Solution

position: 728951643315476829496283715971624358863519472254738961582347196149865237637192584 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 # A3: 4,5 => UNS
* INC # B3: 4,5 => UNS
* INC # C3: 4,5 => UNS
* DIS # C4: 4,5 => CTR => C4: 1,3,7
* INC # C4: 1,3,7 => UNS
* INC # C6: 4,5 => UNS
* DIS # C7: 4,5 => CTR => C7: 1,2,6
* INC # C7: 1,2,6 => UNS
* DIS # C9: 4,5 => CTR => C9: 3,6,7
* INC # C9: 3,6,7 => UNS
* INC # F4: 4,9 => UNS
* INC # F6: 4,9 => UNS
* DIS # B5: 4,9 => CTR => B5: 3,6
* INC # B5: 3,6 => UNS
* INC # G5: 4,9 => UNS
* DIS # C5: 2,6 => CTR => C5: 3,4
* INC # C5: 3,4 => UNS
* INC # A6: 2,6 => UNS
* INC # C6: 2,6 => UNS
* INC # E7: 4,6 => UNS
* INC # E9: 4,6 => UNS
* DIS # A8: 4,6 => CTR => A8: 1
* PRF # A8: 1 => SOL
* PRF # B8: 4,6 => SOL
* INC # B8: 3,7 => UNS
* DIS # I8: 4,6 => CTR => I8: 7
* PRF # I8: 7 => SOL
* CNT  27 HDP CHAINS /  27 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # A3: 4,5 => UNS
* INC # B3: 4,5 => UNS
* INC # C3: 4,5 => UNS
* DIS # C4: 4,5 => CTR => C4: 1,3,7
* INC C4: 1,3,7 # C6: 4,5 => UNS
* DIS C4: 1,3,7 # C7: 4,5 => CTR => C7: 1,2,6
* DIS C4: 1,3,7 + C7: 1,2,6 # C9: 4,5 => CTR => C9: 3,6,7
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # C6: 4,5 => UNS
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # C6: 2,6 => UNS
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # A3: 4,5 => UNS
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # B3: 4,5 => UNS
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # C3: 4,5 => UNS
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # C6: 4,5 => UNS
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # C6: 2,6 => UNS
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # F4: 4,9 => UNS
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # F6: 4,9 => UNS
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 # B5: 4,9 => CTR => B5: 3,6
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 # G5: 4,9 => UNS
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 # G5: 4,9 => UNS
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 # G5: 3 => CTR => G5: 4,9
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 # F4: 4,9 => UNS
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 # F6: 4,9 => UNS
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 # C5: 2,6 => CTR => C5: 3
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 + C5: 3 # E7: 4,6 => UNS
* INC C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 + C5: 3 # E9: 4,6 => UNS
* DIS C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 + C5: 3 # A8: 4,6 => CTR => A8: 1
* PRF C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 + C5: 3 + A8: 1 => SOL
* STA C4: 1,3,7 + C7: 1,2,6 + C9: 3,6,7 + B5: 3,6 + G5: 4,9 + C5: 3 + A8: 1
* CNT  27 HDP CHAINS /  26 HYP OPENED