Merge pull request #3357 from Abigail/abigail/week-096

Abigail/week 096

2 files changed, 31 insertions, 16 deletions

diff --git a/challenge-096/abigail/lua/ch-1.lua b/challenge-096/abigail/lua/ch-1.lua
index 9c4b1de913..c2de0434f6 100644..100755
--- a/challenge-096/abigail/lua/ch-1.lua
+++ b/challenge-096/abigail/lua/ch-1.lua
@@ -1,9 +1,19 @@
+#!/opt/local/bin/lua
+
+--
+-- See ../README.md
+--
+
+--
+-- Run as: lua ch-1.lua < input-file
+--
+
 for line in io . lines () do
     --
     -- Extract words and put them into an array, in reverse.
     --
     local words = {}
-    for str in string . gmatch (line, "[^ ]+") do
+    for str in string . gmatch (line, "[^%s]+") do
         table . insert (words, 1, str)
     end
 
diff --git a/challenge-096/abigail/lua/ch-2.lua b/challenge-096/abigail/lua/ch-2.lua
index 162f06eef0..99058213ca 100644..100755
--- a/challenge-096/abigail/lua/ch-2.lua
+++ b/challenge-096/abigail/lua/ch-2.lua
@@ -1,3 +1,13 @@
+#!/opt/local/bin/lua
+
+--
+-- See ../README.md
+--
+
+--
+-- Run as: lua ch-2.lua < input-file
+--
+
 --
 -- This is an implementation of the Wagner Fischer algorithm, which
 -- calculates the Levenshtein distance.
@@ -7,18 +17,13 @@
 function LevenshteinDistance (first, second)
     local n = first  : len ()
     local m = second : len ()
-    if n < m
-    then
-        first, second = second, first
-        n,     m      = m,      n
-    end
-    distances = {}
+    distance = {}
     for i = 0, n do
-        distances [i] = {}
+        distance [i] = {}
         for j = 0, m do
             if i == 0 or j == 0
             then
-                distances [i] [j] = i + j
+                distance [i] [j] = i + j
             else
                 local cost = 1
                 if string . sub (first,  i, i) ==
@@ -26,10 +31,10 @@ function LevenshteinDistance (first, second)
                 then
                     cost = 0
                 end
-                distances [i] [j] = math . min (
-                    distances [i - 1] [j]     + 1,
-                    distances [i]     [j - 1] + 1,
-                    distances [i - 1] [j - 1] + cost
+                distance [i] [j] = math . min (
+                    distance [i - 1] [j]     + 1,
+                    distance [i]     [j - 1] + 1,
+                    distance [i - 1] [j - 1] + cost
                 )
             end
         end
@@ -37,14 +42,14 @@ function LevenshteinDistance (first, second)
         --
         -- We only need the previous row, so we can return the
         -- memory of rows before that. This reduces the memory
-        -- usage from O (n * m) to O (min (n, m))
+        -- usage from Theta (n * m) to O (n + m)
         --
         if i > 0
         then
-            distances [i - 1] = nil
+            distance [i - 1] = nil
         end
     end
-    return distances [n] [m]
+    return distance [n] [m]
 end