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11 votes

Keys and Locks Puzzle

I believe the condition is: This condition is sufficient. Is this condition necessary?
Florian F's user avatar
  • 30.6k
8 votes
Accepted

Filling a rectangular grid with holes using tetrominoes

No, it isn't always possible. Consider this 5-by-3 grid with 3 cells painted black. The 12 white cells can't be split into 3 tetrominos because the four corner cells must be in different tetrominos --...
xnor's user avatar
  • 27.3k
7 votes
Accepted

Keys and Locks Puzzle

The exact condition is Actually, something slightly stronger is true: A strategy is winning if and only if We can prove this equivalence by an application of Suppose we are handed any strategy. ...
Tim Seifert's user avatar
  • 1,743
6 votes
Accepted

The HH vs HT question

One important thing to note that if I'm going to show there is a sort of bijection between So what is this bijection between
Tyler Seacrest's user avatar
4 votes

Keys and Locks Puzzle

I thought of it in terms of a Suppose Can this always be done?
Tyler Seacrest's user avatar
2 votes

Tile dominoes in a 3x10 space

Lemma: The proof should be trivial and is omitted here. From this, we derive the recurrence relation Now, it is trivial to evaluate the final answer: and finally,
Auride's user avatar
  • 797

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