Hi,

I'm new here but after googling a whole day, I couldn't find another solution then to ask you guys on this forum about some help for my problem.

I believe it's more advanced type of sub-sum problems. More advanced because sub-summing is limited only to '+' operations, here I have both, the '+' and '-' operations.

Here's the problem itself:

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A set of natural numbers is given. Generate all the subsets of this set joined by alternating + and - operators which

sum up to exactly S. .

I/O description. Input: enumeration of elements in the set, on one line, then sum on one line e.g.

1 3 5 7 2 6

0

Output: enumeration of elements resulting in the given sum, e.g.

1-3+2

1+3-6

5-7+2

1+5-6

...

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I thought a possible solution would be the generation of a matrice(table) in wich I would start placing 1 or -1 or 0 for each cell. But I didn't succed at all.

I thought maybe someone already had to deal with such a problem, but on the web I cound't find it's solution...

Thank you in advance...