CFOP Quick-witted Princess Leia (F2L completion guessing)

Tito_H

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Episode XX+1

Princess Leia
was in trouble again.
She was in the commander’s
room in the Death Star, surrounded
by Darth Sidious, Darth Vader, Tarkin, etc…

The Superlaser of the Death Star was aiming at the Earth.

Death Sidious said to Leia, “You could scarcely won the challenge1 and the challenge2. But I am pretty sure you will fail this time.”

He pulled a scrambled Rubik's cube out of his loose sleeve, and said, “I will destroy the Earth if you can not complete the F2L in 5 seconds.”

(Picture from front side)
6592F3CD-9941-4673-A6DD-2574FC3C78DE.jpeg

(Picture from back side)
E96041CD-3A0D-4003-8673-903DCC01C40C.jpeg

(Picture from bottom side)
7495468B-0C70-45FA-9A16-89C1D6062745.jpeg

(Source: https://filipeteixeira.com.br/new/picturecube/)

He handed the cube to her, and gave her 10-second inspection time.

He added, “Don’t peep into the left, back, or bottom face. The Cross and 2 F2L (2 left slots) are already completed for you. To use the Force or to pop the pieces out of the cube is strictly prohibited!”

Darth Sidious knew that Princess Leia's skill level was Sub-20, and that it took her about 12 seconds to complete 4 F2L. He had calculated that it would take her about 6 seconds to complete 2 F2L, giving her a less than 50% chance of success.

She thought to herself, "I've got it!" Anticipating something like this, she had been secretly training since then, and now she has reached Sub-17 level, and can complete 4 F2L in under 10 seconds.

She examined the cube, and found Blue-Red pair was already matched up, and another pair (Red-Green) was a little tough to slot in backside, but thought she could manage it.

He suddenly shouted, “Time up. Get started!”

But he was always unfair, and just before she started to execute the first move, he said, “Oh, I almost forgot to tell you one more condition. You must complete the F2L within 8 moves on a STM base.”

She was angry and yelled at him, "Not again, you cheating old man!" but he wouldn't listen and there was nothing she could do.

She was upset when she realized that all the moves she had thought up during the inspection time would result in 9 moves. She muttered, "I don't have time, what should I do?"

Can you help her?
 
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Now that I can reproduce the cube, using the simulator of this forum, I attach it for your easy handling.



I hope someone can help the Princess Leia…
 
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Not sure what the goal is. If the goal is to solve 2 layers in 8 moves in STM, then



You realize that solving programs like Cube Explorer exist, right?

R D B' D' R' U' L U L' (9f*)
R' U' R L B U' B' U2 L' (9f*)
R' U' L U R L' B U' B' (9f*)
R' U' L U L' F' U' F R (9f*)
R' U' L U2 F' U' F R L' (9f*)
R' U' L F' U2 F U R L' (9f*)
R' U' L F' U' F R U L' (9f*)
R' F' U' L U L' U' F R (9f*)
R' L F' L' U' L2 F R L2 (9f*)
L B U' B' L' U' L U L' (9f*)
B U' L' B' L U2 L U' L' (9f*)
B U' L' B' L U' L U2 L' (9f*)
B U' B2 U B U' L U L' (9f*)
B L U' F' L' B' L2 F L2 (9f*)
 
Yes, the goal is to solve 2 layers in 8 moves in STM. Thanks to bcube's help, we were able to save Princess Leia and the Earth.

I'm an old-school analog guy, so I don't know any programs like Cube Explorer. I prefer everyone solving the problem by hand without using such programs, although I know that unlike me, who's already retired, he/she probably don't have the time to waste on such manual labor… Nevertheless, sometimes humans come up with answers that programs can't do 😏

Anyway, let's continue with what Princess Leia did.

With only 9 moves to complete F2L (2 layers) in her mind, Princess Leia had 1 second left. At that moment, she said, "Sidious, time out! Listen to my interesting proposal."

Sidious replied, "There's no rule about time outs. This is not a NBA. But since you say it's interesting, I'll listen."

Princess Leia then asked, "Let's make a bet on whether it's possible to solve F2L(2 layers) of this cube in 7 moves in STM. I'll bet it's possible. What do you think?"

Sidious thought to himself, 'What a stupid thing she's saying! I've already looked up that 8 moves is the minimum number of moves when scrambling the cube,' and said, "Then, I'll bet on the impossible. If you win, I'll stop destroying the Earth. If you lose, I'll destroy it."

So, readers, what do you think Princess Leia has a chance of winning?
 
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Just to be sure, I'd like to modify the direction of the cube to Blue Front, instead of Orange Front. Sorry, bcube.

facelets=rybrybyyywwywwwwwwyooboowoorrgorroyoggbggggggrbbrbbbyr
⇩
facelets=bbyyyyrrywwwwwwwwyrbbrbbbyrbggggggggwbyoooooorrgorroyo

Please use this simulator.
 
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Can someone check if programs like Cube Explorer can present us any algorithm by which this F2L can be solved in 7 moves?
 
Can someone check if programs like Cube Explorer can present us any algorithm by which this F2L can be solved in 7 moves?

I have checked the following case (all 6 optimal solutions in STM found by Cube Explorer are included). If by F2L you meant a different case, specify it.

 
Thanks for checking out Cube Explorer, bcube. My hunch was right. 8 moves was the best sequence, as I suspected.

Now, let's talk about what Princess Leia did.

She realized that she couldn't complete the F2L in 7 moves with the current White Cross, but she could complete it in 7 moves by switching to a different colored Cross.

She then performed the following sequence, switching to a Blue Cross and completing the F2L in 7 moves (as a bonus, OLL skip in this example)😉

 
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