- View Source--- In aima-talk@yahoogroups.com, "Brandon Corfman" <bcorfman@a...>

wrote:> I'm not sure what you mean by "dead end".

What I means:

"dead end" means "It is impossible to further expand the node, that's

no possible action"

If a node can be broken> down, into a new center node and two leaves, then at some point, the

further

> whole process will stop because there are no more operations to be

> performed. (In other words, how can you break down 2 down any

> than 1 + 1 in the operations given?)

According the books guide, it is allowed to break down

("expand") "1+1". For example:

1. replace the first "1" in "1+1" state by "(1+1)+1

2. replace the first "1" in "1+1" state by "(1+n)+1

3. replace the first "1" in "1+1" state by "(n+n)+1

4. replace the first "1" in "1+1" state by "(n+1)+1 (One of my

question is "delete this action or not, because this is same as above

item "2")

5. replace the first "1" in "1+1" state by "(1-1)+1

6. replace the first "1" in "1+1" state by "(n-1)+11.

7. replace the first "1" in "1+1" state by "(n-n)+1

7. replace the first "1" in "1+1" state by "(1-n)+1

...

...

...

Thank you for your attention.

kind regards/chenyu

>

tree

> I think that you are breaking things down too far. If you have a

> with all 1's or n's at leaf nodes and +,-,/, or * in the internal

wrote:

> nodes, then the problem seems to indicate that that should be your

> goal condition.

>

> This is speculation, since I haven't worked through the problem

> myself, but these are my initial impressions.

>

> Brandon

>

> --- In aima-talk@yahoogroups.com, "chenyu468" <chenyu468@y...>

> > hi everyone,

for

> > 1. According to the guide, it is necessary to build a binary-tree

> > representing the "state". The tree's leaves are "1" or "n" and

path

> > internal nodes are "+" "-" "*" "/" "exp" operator.

> >

> > 1. I don't know how to check the "dead end" for expression. If

> > no "dead end" check, it seems that only "breadth_first_search" is

> > acceptable. The the speed and space complexity is too high.

> >

> > 2. the "action" set for replacing "1" is 16 (20-4) by deleting "n

> > divide n", "1 divide 1", "1 multiply 1", "exp(1,1)", "

> > for replacing "n" is also 16 for the similar reason.

> > The expanding branch factor is too high (16). How to reduce it?

> >

> > 3. I don't know how to identify the "same state" from different

> > for avoiding expanding them. Could you tell me? Or is it possible

to

> > create unique tree everytime, therefore no need to identify them

are

> > the same state or not?

> >

> > Thank you in advance.

> > kind regards/chenyu