Newest Questions
29,037 questions
49
votes
4
answers
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Which switch goes to which bulb?
You are in a room with three switches, labeled A, B, and C. Initially, each switch is in an off state. In an adjoining room, there are three incandescent light bulbs. Your task is to correctly ...
- 3,720
25
votes
3
answers
2k
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In the iterated Prisoner's Dilemma, how would a change in the payoff matrix affect strategy?
Quick summary of the Prisoner's Dilemma: Two criminals are charged with a crime. Each is given an opportunity by the police to confess.
If they both stay silent, they don't have enough evidence to ...
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37
votes
4
answers
18k
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How many chess pieces does it take to "cover" all spaces on a chessboard?
Given an 8x8 chessboard, your goal is to "cover" each space on the board with the fewest possible number of pieces. A space is "covered" if there is a piece on it, or if a piece on the board can be ...
- 3,720
37
votes
4
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27k
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Why is a single-corner twist not a valid position on a Rubik's cube?
For those of you familiar with the solution to the Rubik's cube, you will know that a single-corner twist is not a valid position. It can neither be attained by scrambling, nor can it be solved if it ...
user20
8
votes
2
answers
23k
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How can I fix "stuck" positions on the Void Rubik's Cube (using the standard beginner's method)?
Sometimes, when solving the Void Rubik's Cube using the standard beginner method, it gets "stuck." What I mean by this is that the top edge of one face and the top edge of an adjacent face's colors ...
- 4,677
32
votes
4
answers
22k
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Learning to Solve a River Crossing Puzzle
I have seen many variations of the following puzzle:
Once upon a time, a farmer went to the market and purchased a fox, a goose, and a bag of beans. On his way home, the farmer came to the bank of ...
- 3,720
125
votes
7
answers
31k
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100 Prisoners' Names in Boxes
Names in Boxes
The names of 100 prisoners are placed in 100 wooden boxes, one name to a box, and the boxes are lined up on a table in a room.
One by one, the prisoners are led into the room; each may ...
- 2,047
34
votes
3
answers
6k
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How can I procedurally generate Sokoban puzzles?
How can Sokoban puzzles be procedurally generated with a computer program, guaranteeing at least one solution?
A simple algorithm might be:
...
- 4,677
59
votes
11
answers
103k
views
Are there published Sudoku puzzles that require guessing?
I believe in a number of books I have read and solved myself, the introduction stated that guessing should never be necessary for any of the puzzles in the book. Instead, a handful of techniques ...
- 701
31
votes
2
answers
6k
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How many queens can be on a chessboard without attacking each other?
What is the maximum number of queens that can be placed on a standard 8x8 chessboard such that no one of them is capable of attacking any of the others in a single move?
- 3,720
61
votes
4
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What is the maximum number of solutions a Sudoku puzzle can have?
I've seen Sudoku puzzles that can be solved two different ways. Referring to a traditional 9x9 grid:
Is it possible for a Sudoku puzzle to have more than two solutions? If so, what is the maximum ...
- 2,543
30
votes
2
answers
2k
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Are there "rules" (or consistent conventions) that limit when the NY Times Crossword can deviate from rotational symmetry?
Most American crosswords use rotational (or "radial") symmetry so that squares directly opposite each other (through the center) are identical.
In the Times, I've only seen this not be the case ...
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