require 'pp'
ary = %w(w1 w2 w3 w4 w2 w3 w1 w1 w5 w2 w3 w4)
window = 6
hout = Hash.new
ary.size.times do |i|
ary[i+1, window].each do |w|
next if /#{ary[i]}/ =~ w
hout[w] = 0 unless hout[w]
hout[w] += 1
end
end
pp hout