580 likes | 666 Views
Basis & Structure. Center. Surface 6 of them, 6 colors Center Cube 6 of them (fixed) Edge Cube 12 of them Corner Cube 8 of them. Corner. Edge. A1. C1. B1. B2. A2. A4. C2 b. C4. B4. B3. C3. A3. Graph for Edges. Bijection A new game. C4. C3. C1. C2 b. B2. B3. A2.
E N D
Basis & Structure Center • Surface • 6 of them, 6 colors • Center Cube • 6 of them (fixed) • Edge Cube • 12 of them • Corner Cube • 8 of them Corner Edge
A1 C1 B1 B2 A2 A4 C2 b C4 B4 B3 C3 A3 Graph for Edges • Bijection • A new game C4 C3 C1 C2 b B2 B3 A2 B4 A3
A4 C4 B1 B2 A1 A1 C1 A1 B4 B3 C1 C1 B1 B1 B2 B2 A3 C2 b C3 A1 A4 A4 C2 C2 b A2 A2 C4 C4 A2 C4 B1 B2 B3 A3 B4 C3 B3 C3 C1 A4 A2 B3 B4 A3 A3 C2 b C3 B4 Operation
8 1 7 2 3 6 4 5 Graph for Corners 2 3 • Bijection • Corners numbered in order • Another new game 1 4 7 (inside) 8 5 6
4 8 4 1 3 3 7 7 1 2 1 2 2 6 3 6 6 7 5 4 5 8 5 8 8 4 7 1 2 6 3 5 Operation
O B Y W G R Edge State • in right position, can be error • A state parameter needed • Consider certain color & its opposite color • B VS G • W VS Y • O VS R
B’ B B B B B 0 0 0 A A Red Red A Red A Red A’ Red Red A’ Case 1 • Both with same or opposite color • e.g. AA BB or A’A BB’ or A’A BB • PS: A completed Rubik cube’s edges all have a parameter 0
B’ B A A B A 1 1 1 B B Red Red B Red A Red A’ Red Red A’ Case 2 • Both not with same or opposite color • e.g. AB AB or A’B AB’ or A’B AB
B B A B 1 0 Red A Red B Red C / C’ Red C / C’ Case 3 & 4 • Irrelevant color involved • e.g. CA BB state 1 (Case 3) • e.g. CB AB state 2 (Case 4)
Corner State • Top/Bottom face state 0 (when completed, final state) • Clockwise face state 1 (when completed, final state) • The face left state 2 (when completed, final state) • State parameter = current state face’s parameter (current state) State face 0 Top State Surface 1 Bottom StateSurface (inside) 2
8 1 7 2 3 6 4 5 Operation (Considering state) • Case 1: Vertical • State unchanged
8 - 1 + 7 + - 2 + 3 - 6 4 - 5 + • Case 2: Horizontal • State changing as left graph • Simply +1 or -1
8 + 1 - 7 - + 2 - 3 + 6 4 + 5 - • Case 3: w.r.t. axis • State changing as left graph • Simply +1 or -1
1st Layer • Observation + Operation • Locus Method • Avoidance Method
c b d a f e Locus Method • Possible position after one operation • b, c, d, e, f and a: relative locus
Steps & Example • Target & destination square relative locus • Destination Public locus • Target replaces the destination one • If needed, target somewhere irrelevant to the Destination before any operation Public Locus 2 3 1
Avoidance Method • Sometimes, some other squares’ position may be affect when moving the target square to its destination position • Like the last step in Locus Method • But this time, we need to deal with 2 blocks
Steps & Example • target block somewhere irrelevant to the Destination before any operation 2 3 1
2nd Layer • Try & error some method • some method derived method
A1 A1 C1 C1 B1 B1 B2 B2 A1 A4 A4 C2 b C2 b A2 A2 C4 C4 C4 B1 B2 B3 A3 C3 B4 C3 B3 C1 A4 A2 B3 B4 A3 A3 C2 b C3 B4 Method A
A1 A1 C4 B1 B2 B3 B1 B2 C1 A4 A2 B3 C4 A4 A2 C3 A1 B4 C2 C3 C1 B4 C2 b B3 B1 C4 A3 A3 B2 A4 C2 b C3 A2 C1 B4 A3
A1 A1 C2 b B1 C4 C2 b B1 B2 B2 C1 A4 B3 A2 A4 C4 B3 A2 C3 B4 C1 C3 B4 A3 A3
A1 C1 B1 B2 A2 A4 C1 B4 A3 Method B • change alltoand allto • change the 5th and 7th steps from right-switching to left-switching • method A method B • Always check the states
3rd Layer • Last layer • More cubes’ position & state cannot be changed
A1 A1 C1 B1 A2 B3 B2 A4 C4 C1 B1 B2 C2 B4 C3 A1 A4 C2 A2 C4 A3 B2 B1 A2 B3 B4 C3 B3 C3 A4 C1 A3 C4 C2 B4 A3 Method C
A1 A1 B2 B1 A2 C1 B1 A2 B3 C3 A4 C1 B3 C2 b A4 B2 A1 C4 C2 A3 C3 C4 A3 B4 C1 B1 A2 B4 B3 C2 b A4 B2 A1 B4 C3 C4 C1 B1 B2 A3 A2 C2 A4 C3 B3 B4 C4 A3
D-0 D-0 A-0 C-1 C-0 B-0 B-0 A-1 Observation • No change in both position and state of the bottom and 2nd layers. • But an obvious change in the top layer. • Let C1, 2, 3 and 4 be A, B, C and D, --- state parameter followed + +
A1 A1 C3 B1 C1 C4 B1 C1 C4 B2 A4 C2 b B2 B3 A4 C3 A2 B4 B3 A2 B4 C2 A3 A3 Method D
A1 A1 C3 B1 C1 C4 B1 C1 C4 B2 A4 C2 b B2 B3 A4 C3 A1 A2 B4 B3 A2 B4 C2 C3 B1 B2 A3 A3 A2 C1 A4 C2 b C4 B4 B3 A3
A1 A1 C2 B1 B2 C2 B1 C3 A2 A4 C3 B3 B2 A4 C4 B3 C4 C1 B4 A2 C1 B4 A3 A3 A1 A1 C1 B1 C3 C1 B1 B2 B2 C4 A4 B3 A2 C4 A4 C3 A2 C2 B4 C2 B3 B4 A3 A3
D-0 D-0 A-0 A-0 C-0 B-1 B-0 C-1 Observation • No change in both position and state of the bottom and 2nd layers. • Butobvious change in the top layer • Let C1, 2, 3 and 4 be A B, C and D, --- state parameter followed + +
D-0 D-0 D-0 D-0 D-0 A-0 A-0 C-1 A-0 A-0 B-0 B-0 B-0 C-0 C-0 C-0 B-0 C-0 A-1 B-0 Method E • Derived by method C & D use in a different direction method C + + + + method E
C1 C1 C4 Ck C2 Cp C3 Cq Demonstration • Arbitrary start • Deal with the top layer • Put C1 to the correct positionbut not consider its state parameter All state parameters are 0 start target Unknown state parameter
C1=1 Cp C1=0 Ck Ck C1=0 Cp Cp Cq Cq Cq Ck Demonstration (cont.) • Case 1: C1 = 0completed Jump to next step • Case 2: C1 = 1 use method D method D
Demonstration (cont.) • A completedRubik Cube’s every edge cube’s state parameter is 0 • After everyoperation, the total parameter changes is +4 • i.e. the total parameter must be an even number. • A1~4, B1~4,C1 all equal to 0 • C2,C3 and C4: can’t be one ‘1’ or three ‘1’ among them
Demonstration (cont.) • Case 1: no ‘1’ among C2, C3 and C4 • i.e. C1=0, C2=0, C3=0, C4=0 use method E • Case 2: 2 ‘1’ among C2, C3, C4. • If these 2 ‘1’ are adjacent use method D • change both of them to ‘0’ case 1 • If these 2 ‘1’ are not adjacent use method C • change both of them to ‘0’ case 1.
Method F • Corners of the top layer left after the previous steps • More and more complicated • TASK: deal with the 4 corners • CAUTION: cannot affect the other 22 cubes • A new method needed
A1 A1 A1 C4 A2 A4 C4 B1 A2 C1 B1 B2 C1 B1 B3 B4 C1 A4 B3 C3 A4 C2 A2 C4 C2 C3 C2 B2 B4 B2 B3 B4 C3 A3 A3 A3 A1 C1 B1 A2 B2 A4 B3 C4 C2 B4 C3 A3
A1 C1 A2 A4 B2 B3 B4 C4 A1 C2 b C3 A1 B1 C1 B2 A4 C4 A3 B2 A4 C2 b A2 B4 C4 C1 A2 B1 B4 C3 B3 B1 C3 B3 C2 b A3 A3
A1 A1 C4 C1 B1 B2 B2 B1 A2 C1 A2 C3 C4 A4 A4 C3 B3 B4 C2 b B3 B4 C2 b A3 A3 UNCHANGED
All edge cubes’ parameter equal to 0 • No changes occurred • Table of state parameter omitted • Consider corners
3 8 3 8 3 3 8 8 8 7 1 3 3 4 4 7 1 1 7 7 8 8 7 7 8 7 8 1 2 2 2 4 7 7 2 2 6 3 2 2 6 1 2 2 1 6 5 6 5 6 6 6 5 5 1 3 6 6 4 1 3 4 1 4 5 5 4 4 5 5 5 4
Observation • Corner 1, 3 and 4 change their position • State parameter +1 • Other 22 cubes remain unchanged
A1 A1 C1 C1 B1 B1 B2 B2 A4 A4 C2 b C2 b A2 A2 C4 C4 B3 B3 B4 B4 C3 C3 8 8 1 3 A3 A3 7 7 2 2 3 4 6 6 1 4 5 5 Method G • Derived by Method F (Opposite process ) UNCHANGED! 1.3 and 4 corners’ parameters minus 1
Last 4 Corners • Divide into 2 parts • 1. Change all the parameter to 0 • 2. Switch them to the correct position
Part 1 • Sum of all parameters must be a multiple of 3 • Case 1: 0, 0, 0, 0 • Case 2: 0, 1, 1, 1 • Case 3: 0, 0, 1, 2 • Case 4: 0, 2, 2, 2 • Case 5: 1, 1, 2, 2