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A puzzle based on combinatorics, which is the study of counting discrete structures. Use with [mathematics]

6 votes
Accepted

Class Seating Arrangement

The answer is Because As such Note that with $9$ students this would be: In general for squares of side $n$ these are the ...and for rectangles of sides $m,n$ the result has
Jonathan Allan's user avatar
3 votes

Sticky sticky stick stick

This may not yet be isn't quite the best...
Jonathan Allan's user avatar
3 votes
Accepted

Move 10 sheep on another shore

I can, using a method devised below, do it in Starting with a simple case, 1_0, it's pretty obvious the optimal steps are: 1_0 1_0 _10 or 10_ 01_ _01 0_1 0_1 both of whi …
Jonathan Allan's user avatar
7 votes
Accepted

How many different kinds of rings are there?

In the language of combinatorics the number of symbols, assuming only purely rotational and reflectional geometric symmetry* is: * as pointed out by Ian MacDonald and Silenus, this has not been guaranteed …
Jonathan Allan's user avatar
4 votes

In a square, arrange the binary numbers such that no $n$:th digit is the same along a row or...

For what it's worth
Jonathan Allan's user avatar
6 votes
Accepted

A weird Shepherd with his sheep

The answer is Because I used this Python code: Reduced bounds from before I started a search... Because A lower value for the upper bound is: Lowered further by @astralfenix to …
Jonathan Allan's user avatar
5 votes

The L-Game of Life

The board Because Furthermore
Jonathan Allan's user avatar
5 votes

Three Stacks N cards

An upper bound is Note that Now we can Some code: def squarePairs(n): for a in range(1, n + 1): for b in range(a + 1, n + 1): if ((a + b) ** .5) % 1 == 0: …
Jonathan Allan's user avatar
2 votes

Three Dice minimum value

I wrote a program to search for such dice. It found $29$ with maximum faces of It finds none with maximum faces of less. Here are those dice: The program works by first finding all ($71$ after …
Community's user avatar
  • 1
6 votes
4 answers
544 views

My time-travelling adventure

I just had a fun visit from a time traveller and she offered to whisk me off for a whirlwind tour – she offered to take me to observe any one time for each of any choice of distinct years from $1$C.E. …
3 votes
Accepted

The Building, the Elevator and the Milkwoman

If we also know that all the children are residents then there are There are $80$ residents at home All residents have the same probability, $p$, of taking the elevator at a certain time (eith …
Jonathan Allan's user avatar
14 votes
Accepted

LEVEL connections

Without allowing backtracking along edges Since The paths
Jonathan Allan's user avatar
5 votes

Arranging a long line of cards - part 2

I will put this out there, since enumeration seems to hold, although I can't quite see how it's the answer yet (i.e. what the base choices actually are that lead to this result). What is this? . …
Jonathan Allan's user avatar
1 vote

My time-travelling adventure

Here is my generic solution. Code to perform $_nC_k$: def choose(n, k): '''Returns the number of ways to choose k items from n items''' reflect = n - k if k > reflect: if k > n: …
Jonathan Allan's user avatar
6 votes
Accepted

Engel's Enigma Optimals

As you say, you are implementing a type of Douglas Engel's puzzle, an "Enigma". Given the colour set and the fact that you are ignoring the orientation of the triangular wedges ("corners" in twisty pu …
Community's user avatar
  • 1

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