Programming Puzzles Group

When

What

We are a group of guys who like puzzles and use programming to understand them better.

Map

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Where

Maan Coffee

northwest corner of Gongti. Table by the north door.

Wechat: 360414628

Email

Ernie
ernie@beijinggoclub.com

Github

github code

Meeting #4 - polyomino further questions June 23 2014

• we have code for simple additions
• will look at the pentomino "combination table"

Meeting #3 - Pentominos Continued - June 16, 2014

• 3 people
• 
• 
• A list of properties of Pentominos. For any grouping, could we come up with a property dividing them that way? Yes, at least a horrible, explicit way. But is there an interesting property for each one?
• 

• The things we'd like to discover about pentominos

• Formula for how many polyominos of N squares are there?
• Algebra for sets of polys
• Combine/separate shapes into polys of size N (some shapes are splittable in different ways)
• are there things about group theory we can apply? additive identity, multiplicative identity, elementary units?

• general formalus for certain types of combinations

  I + I_n for example is pretty easy, as is N+I_n. But varying both isn't easy, and as they bend on themselves it gets harder too. But it's a promising avenue - for a given shape it is easy to calculate what the formula for combinations with I_n is. How broadly can this be done?
• 
• 
• 

Meeting #2 - pentominos

• 2 people.

• Properties of Pentominos

• Groupings:
• edges
• perimeter
• inner corners
• outer corners
• longest edge
• covering square size
• "missing" squares to complete a rectangle
• etc.
• 
• 
• wikipedia pentominos
• naming them: we use F,I,L,N,P,T,U,V,W,X,Y,Z
• question: for every grouping, does there exist a property which produces it?
• counting pentominos - it's surprisingly unclear how many there are with N squares.
• multiplying (adding) pentominos. How many free combinations of X&I are there
• Families / relatedness graphs - grouping pentominos based on how many single-square moves are necessary to convert one to the other. For example, I=>P = 2, I=>F,L=1 etc. There doesn't seem to be any sense to it.
• 

Meeting #1 - 2048

• We discussed the game 2048. 4 people.
• Maximum score reachable?
• "pure" version - only 2s, no random placement
• "evil" version
• developing an AI - strategies:
  -"entropy" - minimize gradient of differences between adjacent squares
  -"survival" - with enough depth to the search, just surviving should be the prime board evaluation function