Analysis of zz-google-002-base.sdk

Contents

Original Sudoku

level: medium

Original Sudoku

position: ..4.2.....9..8.....17..5..24..23.....58.7..2...2.....7.25.9.3..74.............81. initial

Autosolve

position: 584.2.7..29..875...17..5.8247.23.158158.7..23..2518..7825.9.37.7418.32.....7.281. autosolve
Autosolve

Pair Reduction Variants

Pair Reduction Analysis

Pair Reduction Analysis

The following important HDP chains were detected:

* DIS # H2: 3,6 => CTR => H2: 4
* DIS # C9: 9 => CTR => C9: 3,6
* DIS # D3: 3,6 => CTR => D3: 4,9
* PRF # D3: 4,9 => SOL
* DIS # A9: 3,6 => CTR => A9: 9
* PRF # D3: 4,6 => SOL
* DIS # G3: 4,6 => CTR => G3: 9
* PRF # G3: 9 => SOL
* PRF # I1: 1,6 => SOL
* DIS # I1: 9 => CTR => I1: 1,6
* DIS # D2: 1,6 => CTR => D2: 3,4
* DIS # A6: 3 => CTR => A6: 6,9
* DIS # C9: 6,9 => CTR => C9: 3
* DIS # A6: 9 => CTR => A6: 3,6
* DIS # F5: 6,9 => CTR => F5: 4
* DIS # G6: 6,9 => CTR => G6: 4
* DIS # F5: 6,9 => CTR => F5: 4
* DIS # G3: 4 => CTR => G3: 6,9
* DIS # A9: 3,6 => CTR => A9: 9
* DIS # I8: 5,6 => CTR => I8: 9
* PRF # I8: 9 => SOL
* PRF # I8: 6,9 => SOL
* DIS # I8: 5 => CTR => I8: 6,9
* DIS # H1: 6,9 => CTR => H1: 3
* CNT  24 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 # H2: 3,6 => CTR => H2: 4
* DIS H2: 4 # D2: 1 => CTR => D2: 3,6
* PRF H2: 4 + D2: 3,6 # C9: 3,6 => SOL
* STA H2: 4 + D2: 3,6 + C9: 3,6
* CNT   3 HDP CHAINS /   5 HYP OPENED

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

Details

Positions

..4.2.....9..8.....17..5..24..23.....58.7..2...2.....7.25.9.3..74.............81. initial
584.2.7..29..875...17..5.8247.23.158158.7..23..2518..7825.9.37.7418.32.....7.281. autosolve
584129736296387541317465982479236158158974623632518497825691374741853269963742815 solved

Classification

level: medium

Pairing Analysis

--------------------------------------------------
* PAIRS (14)
C2: 3,6
A3: 3,6
E3: 4,6
I2: 1,6
C4: 6,9
B6: 3,6
F4: 6,9
G5: 6,9
B9: 3,6
E8: 5,6
E9: 4,5
I7: 4,6
H8: 6,9
I9: 4,5

--------------------------------------------------
* CONSTRAINT PAIRS (AUTO SOLVE)
I1,I2: 1.. / I1 = 1  =>  0 pairs (X) / I2 = 1  => 14 pairs (_)
D7,F7: 1.. / D7 = 1  => 16 pairs (_) / F7 = 1  => 17 pairs (_)
D2,I2: 1.. / D2 = 1  =>  0 pairs (X) / I2 = 1  => 14 pairs (_)
F1,F7: 1.. / F1 = 1  => 16 pairs (_) / F7 = 1  => 17 pairs (_)
C2,A3: 3.. / C2 = 3  =>  0 pairs (X) / A3 = 3  => 16 pairs (_)
H1,H2: 3.. / H1 = 3  => 15 pairs (_) / H2 = 3  =>  0 pairs (X)
A6,B6: 3.. / A6 = 3  =>  0 pairs (X) / B6 = 3  => 15 pairs (_)
D1,H1: 3.. / D1 = 3  =>  0 pairs (X) / H1 = 3  => 15 pairs (_)
A3,D3: 3.. / A3 = 3  => 16 pairs (_) / D3 = 3  =>  0 pairs (X)
B6,B9: 3.. / B6 = 3  => 15 pairs (_) / B9 = 3  =>  0 pairs (X)
C2,C9: 3.. / C2 = 3  =>  0 pairs (X) / C9 = 3  => 16 pairs (_)
H2,G3: 4.. / H2 = 4  => 16 pairs (_) / G3 = 4  =>  0 pairs (X)
D5,F5: 4.. / D5 = 4  =>  0 pairs (X) / F5 = 4  => 16 pairs (_)
G6,H6: 4.. / G6 = 4  => 16 pairs (_) / H6 = 4  =>  0 pairs (X)
I7,I9: 4.. / I7 = 4  =>  0 pairs (*) / I9 = 4  =>  0 pairs (X)
D2,H2: 4.. / D2 = 4  =>  0 pairs (X) / H2 = 4  => 16 pairs (_)
E9,I9: 4.. / E9 = 4  =>  0 pairs (*) / I9 = 4  =>  0 pairs (X)
E3,E9: 4.. / E3 = 4  =>  0 pairs (X) / E9 = 4  =>  0 pairs (_)
F5,F7: 4.. / F5 = 4  => 16 pairs (_) / F7 = 4  =>  0 pairs (X)
G3,G6: 4.. / G3 = 4  =>  0 pairs (X) / G6 = 4  => 16 pairs (_)
H2,H6: 4.. / H2 = 4  => 16 pairs (_) / H6 = 4  =>  0 pairs (X)
E8,E9: 5.. / E8 = 5  =>  0 pairs (*) / E9 = 5  =>  0 pairs (X)
I8,I9: 5.. / I8 = 5  =>  0 pairs (X) / I9 = 5  =>  0 pairs (_)
E8,I8: 5.. / E8 = 5  =>  0 pairs (*) / I8 = 5  =>  0 pairs (X)
E9,I9: 5.. / E9 = 5  =>  0 pairs (X) / I9 = 5  =>  0 pairs (_)
C2,A3: 6.. / C2 = 6  => 16 pairs (_) / A3 = 6  =>  0 pairs (X)
C4,F4: 6.. / C4 = 6  =>  0 pairs (X) / F4 = 6  => 20 pairs (_)
B6,B9: 6.. / B6 = 6  =>  0 pairs (X) / B9 = 6  => 15 pairs (_)
E3,E8: 6.. / E3 = 6  =>  0 pairs (*) / E8 = 6  =>  0 pairs (X)
C4,A6: 9.. / C4 = 9  => 20 pairs (_) / A6 = 9  =>  0 pairs (X)
A9,C9: 9.. / A9 = 9  => 20 pairs (_) / C9 = 9  =>  0 pairs (X)
H8,I8: 9.. / H8 = 9  =>  0 pairs (X) / I8 = 9  =>  0 pairs (_)
D3,G3: 9.. / D3 = 9  =>  0 pairs (X) / G3 = 9  =>  0 pairs (_)
C4,F4: 9.. / C4 = 9  => 20 pairs (_) / F4 = 9  =>  0 pairs (X)
A6,A9: 9.. / A6 = 9  =>  0 pairs (X) / A9 = 9  => 20 pairs (_)
C4,C9: 9.. / C4 = 9  => 20 pairs (_) / C9 = 9  =>  0 pairs (X)
I1,I8: 9.. / I1 = 9  =>  0 pairs (X) / I8 = 9  =>  0 pairs (_)
* DURATION: 0:01:03.763899  START: 06:22:59.087105  END: 06:24:02.851004 2017-05-01
* CP COUNT: (37)
* SOLUTION FOUND

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,B6,B9,C2,C4,E3,E8,E9,F4,G5,H8,I2,I7,I9)
* 584.2.7..29..875...17..5.8247.23.158158.7..23..2518..7825.9.37.7418.32.....7.281.
* PAIR C2: 3,6 ROW 2
D2: 3,6,1,4                              # reduction candidate for 3,6
D2: 3,6                                  # 17 pairs
H2: 3,6,4                                # reduction candidate for 3,6
H2: 3,6 => CTR
* 584.2.7..29648753131796548247923.158158.74.23..2518.47825.9.3747418532.....742815
H2: 4                                    # 16 pairs
* PAIR C2: 3,6 COL C
C9: 3,6,9                                # reduction candidate for 3,6
C9: 9 => CTR
* 584.2.7..293.875..617345982476239158158.7.6239325184.7825.9.37.7418.32.....7.281.
C9: 3,6                                  # 20 pairs
* PAIR A3: 3,6 ROW 3
D3: 3,6,4,9                              # reduction candidate for 3,6
D3: 3,6 => CTR
* 584.2.7..29..875...17..598247.23.158158.7.623..2518497825.9.37.7418.32699..7.2815
D3: 4,9 => SOLVED
* 584129736296387541317465982479236158158974623632518497825691374741853269963742815
* PAIR A3: 3,6 COL A
A6: 3,6,9                                # reduction candidate for 3,6
A6: 3,6                                  # 20 pairs
A9: 3,6,9                                # reduction candidate for 3,6
A9: 3,6 => CTR
* 584.2.7..293.875..617345982476239158158.7.6239325184.7825.9.37.7418.32...697.281.
A9: 9                                    # 20 pairs
* PAIR E3: 4,6 BLK 2
D2: 4,6,1,3                              # reduction candidate for 4,6
D2: 4,6                                  # 20 pairs
D3: 4,6,3,9                              # reduction candidate for 4,6
D3: 4,6 => SOLVED
* 584129736296387541317465982479236158158974623632518497825691374741853269963742815
D3: 3,9                                  # 15 pairs
* PAIR E3: 4,6 ROW 3
G3: 4,6,9                                # reduction candidate for 4,6
G3: 4,6 => CTR
* 584.2.7..296.875.13179.5.82479236158158479623632518947825.943767418632...637.281.
G3: 9 => SOLVED
* 584129736296387541317465982479236158158974623632518497825691374741853269963742815
* PAIR I2: 1,6 BLK 3
I1: 1,6,9                                # reduction candidate for 1,6
I1: 1,6 => SOLVED
* 584129736296387541317465982479236158158974623632518497825691374741853269963742815
I1: 9 => CTR
* 584.2.7.9296.875.13179.5.82479236158158479623632518947825.9437674186329..637.281.
* PAIR I2: 1,6 ROW 2
D2: 1,6,3,4                              # reduction candidate for 1,6
D2: 1,6 => CTR
* 584.2.73.293.8754.61734598247.23.158158.7.623.62518497825.9.37.7418632.....7.281.
D2: 3,4                                  # 15 pairs
* PAIR C4: 6,9 BLK 4
A6: 6,9,3                                # reduction candidate for 6,9
A6: 3 => CTR
* 584.2.7..293.875..617345982479236158158.7.623362518497825.9.37.7418632..9367.281.
A6: 6,9                                  # 15 pairs
* PAIR C4: 6,9 COL C
C9: 6,9,3                                # reduction candidate for 6,9
C9: 6,9 => CTR
* 584.2.7..293.875..61734598247.23.158158.7.623.62518497825.9.37.7418632.....7.281.
C9: 3                                    # 16 pairs
* PAIR B6: 3,6 BLK 4
A6: 3,6,9                                # reduction candidate for 3,6
A6: 9 => CTR
* 584.2.7..293.875..617345982476239158158.7.6239325184.7825.9.37.7418.32...697.281.
A6: 3,6                                  # 20 pairs
* PAIR F4: 6,9 BLK 5
D5: 6,9,4                                # reduction candidate for 6,9
D5: 6,9                                  # 16 pairs
F5: 6,9,4                                # reduction candidate for 6,9
F5: 6,9 => CTR
* 584.217.929..87541.1794568247.23.1581584769239325184678251943767418632956..752814
F5: 4                                    # 16 pairs
* PAIR F4: 6,9 COL F
F1: 6,9,1                                # reduction candidate for 6,9
F1: 6,9                                  # 17 pairs
F1: 1                                    # 16 pairs
* PAIR G5: 6,9 BLK 6
G6: 6,9,4                                # reduction candidate for 6,9
G6: 6,9 => CTR
* 584.2.7..29.4875.1.1796548247.23.1581586749239325186478251963747418532..6..742815
G6: 4                                    # 16 pairs
H6: 6,9,4                                # reduction candidate for 6,9
H6: 6,9                                  # 16 pairs
* PAIR G5: 6,9 ROW 5
D5: 6,9,4                                # reduction candidate for 6,9
D5: 6,9                                  # 16 pairs
F5: 6,9,4                                # reduction candidate for 6,9
F5: 6,9 => CTR
* 584.217.929..87541.1794568247.23.1581584769239325184678251943767418632956..752814
F5: 4                                    # 16 pairs
* PAIR G5: 6,9 COL G
G3: 6,9,4                                # reduction candidate for 6,9
G3: 4 => CTR
* 584.2.7..29.4875.131796548247.23.1581586749239325186478251963747418532..6..742815
G3: 6,9                                  # 16 pairs
* PAIR B9: 3,6 BLK 7
A9: 3,6,9                                # reduction candidate for 3,6
A9: 3,6 => CTR
* 584.2.7..293.875..617345982476239158158.7.6239325184.7825.9.37.7418.32...697.281.
A9: 9                                    # 20 pairs
C9: 3,6,9                                # reduction candidate for 3,6
C9: 3,6                                  # 20 pairs
* PAIR E8: 5,6 ROW 8
I8: 5,6,9                                # reduction candidate for 5,6
I8: 5,6 => CTR
* 584.2.7.9296.875.13179.5.82479236158158479623632518947825.9437674186329..637.281.
I8: 9 => SOLVED
* 584129736296387541317465982479236158158974623632518497825691374741853269963742815
* PAIR I7: 4,6 ROW 7
D7: 4,6,1                                # reduction candidate for 4,6
D7: 4,6                                  # 17 pairs
F7: 4,6,1                                # reduction candidate for 4,6
F7: 4,6                                  # 16 pairs
* PAIR H8: 6,9 BLK 9
I8: 6,9,5                                # reduction candidate for 6,9
I8: 6,9 => SOLVED
* 584129736296387541317465982479236158158974623632518497825691374741853269963742815
I8: 5 => CTR
* 584.2.7.929..875.131794568247.23.158158.7.923932518467825.9.3767418632956..752814
* PAIR H8: 6,9 COL H
H1: 6,9,3                                # reduction candidate for 6,9
H1: 6,9 => CTR
* 58432.7..296487531317965482479236158158.7..23.32518.47825.9.37.7418.32...63742815
H1: 3                                    # 15 pairs
H6: 6,9,4                                # reduction candidate for 6,9
H6: 6,9                                  # 16 pairs
* INCONCLUSIVE
* SAVE PR GRAPH zz-google-002-base-pr-000.dot
* REASONING
* DIS # H2: 3,6 => CTR => H2: 4
* DIS # C9: 9 => CTR => C9: 3,6
* DIS # D3: 3,6 => CTR => D3: 4,9
* PRF # D3: 4,9 => SOL
* DIS # A9: 3,6 => CTR => A9: 9
* PRF # D3: 4,6 => SOL
* DIS # G3: 4,6 => CTR => G3: 9
* PRF # G3: 9 => SOL
* PRF # I1: 1,6 => SOL
* DIS # I1: 9 => CTR => I1: 1,6
* DIS # D2: 1,6 => CTR => D2: 3,4
* DIS # A6: 3 => CTR => A6: 6,9
* DIS # C9: 6,9 => CTR => C9: 3
* DIS # A6: 9 => CTR => A6: 3,6
* DIS # F5: 6,9 => CTR => F5: 4
* DIS # G6: 6,9 => CTR => G6: 4
* DIS # F5: 6,9 => CTR => F5: 4
* DIS # G3: 4 => CTR => G3: 6,9
* DIS # A9: 3,6 => CTR => A9: 9
* DIS # I8: 5,6 => CTR => I8: 9
* PRF # I8: 9 => SOL
* PRF # I8: 6,9 => SOL
* DIS # I8: 5 => CTR => I8: 6,9
* DIS # H1: 6,9 => CTR => H1: 3
* CNT  24 HDP CHAINS /  50 HYP OPENED

--------------------------------------------------
* PREPARE PR GRAPH
* PAIR REDUCTION ..
* LEVEL 0 PASS 1 ROUND 1 (AUTO SOLVE) (A3,B6,B9,C2,C4,E3,E8,E9,F4,G5,H8,I2,I7,I9)
* 584.2.7..29..875...17..5.8247.23.158158.7..23..2518..7825.9.37.7418.32.....7.281.
* PAIR C2: 3,6 ROW 2
D2: 3,6,1,4                              # reduction candidate for 3,6
D2: 3,6                                  # 17 pairs
H2: 3,6,4                                # reduction candidate for 3,6
H2: 3,6 => CTR
* 584.2.7..29648753131796548247923.158158.74.23..2518.47825.9.3747418532.....742815
* RESTART
* PAIR C2: 3,6 ROW 2
D2: 3,6,1                                # reduction candidate for 3,6
D2: 1 => CTR
* 584.2.73.29318754661734598247.23.158158.7.623.62518497825.913747418.32.....7.281.
* PAIR C2: 3,6 COL C
C9: 3,6,9                                # reduction candidate for 3,6
C9: 3,6 => SOLVED
* 584129736296387541317465982479236158158974623632518497825691374741853269963742815
* DURATION: 0:00:06.058386  START: 06:24:51.422267  END: 06:24:57.480653 2017-05-01
* SOLUTION FOUND
* SAVE PR GRAPH zz-google-002-base-pr-001.dot
* REASONING
* DIS # H2: 3,6 => CTR => H2: 4
* DIS H2: 4 # D2: 1 => CTR => D2: 3,6
* PRF H2: 4 + D2: 3,6 # C9: 3,6 => SOL
* STA H2: 4 + D2: 3,6 + C9: 3,6
* CNT   3 HDP CHAINS /   5 HYP OPENED

Header Info

* PAIR REDUCTION ..
* ROUND 1: 584.2.7..29..875...17..5.8247.23.158158.7..23..2518..7825.9.37.7418.32.....7.281.
C2: 3,6
D2: 1,3,4,6                              # reduction candidate for 3,6
H2: 3,4,6                                # reduction candidate for 3,6
H2: 3,6 => CTR
* 584.2.7..29648753131796548247923.158158.74.23..2518.47825.9.3747418532.....742815
C9: 3,6,9                                # reduction candidate for 3,6
C9: 3,6 => SOLVED
* 584129736296387541317465982479236158158974623632518497825691374741853269963742815
* SOLVED!

--------------------------------------------------
--------------------------------------------------
quadruple:
D3: 3,4,6,9
G3:   4,6,9
D5:   4,6,9
G5:     6,9
=> D3 = 3

|:step:| 00
--------------------------------------------------

|:info:| alternate

But even without any single row/column constraints:

E9 := !4 => CTR
E9 := 4 => SOL

With single row/column constraints::

I1 := !9 => SOL
I1 := 9 => CTR

Solution

position: 584129736296387541317465982479236158158974623632518497825691374741853269963742815 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 # D2: 3,6 => UNS
* DIS # H2: 3,6 => CTR => H2: 4
* INC # H2: 4 => UNS
* INC # C9: 3,6 => UNS
* DIS # C9: 9 => CTR => C9: 3,6
* DIS # D3: 3,6 => CTR => D3: 4,9
* PRF # D3: 4,9 => SOL
* INC # A6: 3,6 => UNS
* DIS # A9: 3,6 => CTR => A9: 9
* INC # A9: 9 => UNS
* INC # D2: 4,6 => UNS
* PRF # D3: 4,6 => SOL
* INC # D3: 3,9 => UNS
* DIS # G3: 4,6 => CTR => G3: 9
* PRF # G3: 9 => SOL
* PRF # I1: 1,6 => SOL
* DIS # I1: 9 => CTR => I1: 1,6
* DIS # D2: 1,6 => CTR => D2: 3,4
* INC # D2: 3,4 => UNS
* INC # A6: 6,9 => UNS
* DIS # A6: 3 => CTR => A6: 6,9
* DIS # C9: 6,9 => CTR => C9: 3
* INC # C9: 3 => UNS
* INC # A6: 3,6 => UNS
* DIS # A6: 9 => CTR => A6: 3,6
* INC # D5: 6,9 => UNS
* DIS # F5: 6,9 => CTR => F5: 4
* INC # F5: 4 => UNS
* INC # F1: 6,9 => UNS
* INC # F1: 1 => UNS
* DIS # G6: 6,9 => CTR => G6: 4
* INC # G6: 4 => UNS
* INC # H6: 6,9 => UNS
* INC # D5: 6,9 => UNS
* DIS # F5: 6,9 => CTR => F5: 4
* INC # F5: 4 => UNS
* INC # G3: 6,9 => UNS
* DIS # G3: 4 => CTR => G3: 6,9
* DIS # A9: 3,6 => CTR => A9: 9
* INC # A9: 9 => UNS
* INC # C9: 3,6 => UNS
* DIS # I8: 5,6 => CTR => I8: 9
* PRF # I8: 9 => SOL
* INC # D7: 4,6 => UNS
* INC # F7: 4,6 => UNS
* PRF # I8: 6,9 => SOL
* DIS # I8: 5 => CTR => I8: 6,9
* DIS # H1: 6,9 => CTR => H1: 3
* INC # H1: 3 => UNS
* INC # H6: 6,9 => UNS
* CNT  50 HDP CHAINS /  50 HYP OPENED

A2. Pair Reduction

Full list of HDP chains traversed:

* INC # D2: 3,6 => UNS
* DIS # H2: 3,6 => CTR => H2: 4
* INC H2: 4 # D2: 3,6 => UNS
* DIS H2: 4 # D2: 1 => CTR => D2: 3,6
* PRF H2: 4 + D2: 3,6 # C9: 3,6 => SOL
* STA H2: 4 + D2: 3,6 + C9: 3,6
* CNT   5 HDP CHAINS /   5 HYP OPENED