From: William Djaja Tjokroaminata <billtj@...>
Date: 2002-09-19T03:49:59+09:00
Subject: How to Efficiently Calculate the Pattern of Zeros and Ones?

Hi,

I am dealing with this algorithmic problem.  I have an array of arbitrary
integers.  I have to count the occurences of 1's with the pattern

    "0 0 ... 0 1 0 .. 0 0"

in the array.  The minimum number of zeros on each side of the 1 is a
parameter, say m = 2.  Also at the beginning and at the end of the array,
the boundary condition does not require the minimum number of zeros, as
long as they are zeros (or non-existent).

For example, with m = 2:

    [1 0 0 1 0 0 5 1]   --> 2
    [0 0 1 0 0 1 0 2]   --> 1
    [1 0 1 0 1 0 1 0]   --> 0
    [1 0 0 0 0 0 1 0]   --> 2

Typical array length will be around 24.  The problem is I will have
thousands, if not hundreds of thousands, of such arrays.  What is a good
way to do it in Ruby?  (Even coverting the array first to, for example,
string and then use regexp, is also fine as long as it is efficient.)

Regards,

Bill