RosettaCodeData/Task/Levenshtein-distance-Alignment/Ruby/levenshtein-distance-alignm...

37 lines
603 B
Ruby

require 'lcs'
def levenshtein_align(a, b)
apos, bpos = LCS.new(a, b).backtrack2
c = ""
d = ""
x0 = y0 = -1
dx = dy = 0
apos.zip(bpos) do |x,y|
diff = x + dx - y - dy
if diff < 0
dx -= diff
c += "-" * (-diff)
elsif diff > 0
dy += diff
d += "-" * diff
end
c += a[x0+1..x]
x0 = x
d += b[y0+1..y]
y0 = y
end
c += a[x0+1..-1]
d += b[y0+1..-1]
diff = a.length + y0 - b.length - x0
if diff < 0
c += "-" * (-diff)
elsif diff > 0
d += "-" * diff
end
[c, d]
end
puts levenshtein_align("rosettacode", "raisethysword")