From: Heesob Park <phasis@...>
Date: 2008-11-06T23:54:16+09:00
Subject: Re: Combination of numbers in an array that add up to x

2008/11/5 Hae Lee <hae.lee.subscription@gmail.com>:
> Objective: Find list of values in an array that adds up to a specific
> sum.
> -
> I have a list of values in an array:
> [2429.63, 497.87, 51.96, 59.43, 138.4, 66.22, 28.74, 1.75, 2075.13,
> 556.14, 112.56, 116.5, 84.41, 55.97, 139.07, 24.46]
>
> I want to find a combination among these numbers that adds up to a total
> sum of:
> 3435.78
>
> I was hoping a one-liner in irb would do the trick but I haven't found a
> method, etc. that will help me do this.  Thoughts regarding?
If you really want one-liner and the solution exists, try this:

a = [2429.63, 497.87, 51.96, 59.43, 138.4, 66.22, 28.74, 1.75,
   2075.13, 556.14, 112.56, 116.5, 84.41, 55.97, 139.07, 24.46]
t = 3435.78

((s||={})[(a=a.sort_by{rand} while s[a])||a]=1
while(r=(1..a.size).map{|x|a[0,x]}.find{|y|y.inject{|z,n|z+n}==t}).nil?)||r

Regards,

Park Heesob