Data commit

Task/Levenshtein-distance/NetRexx/levenshtein-distance.netrexx

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+/* NetRexx */
+options replace format comments java crossref symbols nobinary
+
+n = 0
+w = ''
+n = n + 1; w[0] = n; w[n] = "kitten sitting"
+n = n + 1; w[0] = n; w[n] = "rosettacode raisethysword"
+
+loop n = 1 to w[0]
+  say w[n].word(1) "->" w[n].word(2)":" levenshteinDistance(w[n].word(1), w[n].word(2))
+  end n
+return
+
+method levenshteinDistance(s, t) private static
+  s = s.lower
+  t = t.lower
+
+  m = s.length
+  n = t.length
+
+  -- for all i and j, d[i,j] will hold the Levenshtein distance between
+  -- the first i characters of s and the first j characters of t;
+  -- note that d has (m+1)x(n+1) values
+  d = 0
+
+  -- source prefixes can be transformed into empty string by
+  -- dropping all characters (Note, ooRexx arrays are 1-based)
+  loop i = 2 to m + 1
+    d[i, 1] = 1
+  end i
+
+  -- target prefixes can be reached from empty source prefix
+  -- by inserting every characters
+  loop j = 2 to n + 1
+    d[1, j] = 1
+  end j
+
+  loop j = 2 to n + 1
+    loop i = 2 to m + 1
+      if s.substr(i - 1, 1) == t.substr(j - 1, 1) then do
+        d[i, j] = d[i - 1, j - 1]   -- no operation required
+        end
+      else do
+        d[i, j] =                 -
+          (d[i - 1, j] + 1).min(  - -- a deletion
+          (d[i, j - 1] + 1)).min( - -- an insertion
+          (d[i - 1, j - 1] + 1))    -- a substitution
+        end
+    end i
+  end j
+
+  return d[m + 1, n + 1]