From 1440839d153c33ae9216bef959c38affab2d32b0 Mon Sep 17 00:00:00 2001
From: Abigail <abigail@abigail.be>
Date: Thu, 21 Jan 2021 16:48:08 +0100
Subject: Add some standard comments and hash bang lines.

---
 challenge-096/abigail/lua/ch-2.lua | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)
 mode change 100644 => 100755 challenge-096/abigail/lua/ch-2.lua

(limited to 'challenge-096/abigail/lua/ch-2.lua')

diff --git a/challenge-096/abigail/lua/ch-2.lua b/challenge-096/abigail/lua/ch-2.lua
old mode 100644
new mode 100755
index 162f06eef0..ef1b039579
--- 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.
@@ -7,11 +17,6 @@
 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 = {}
     for i = 0, n do
         distances [i] = {}
@@ -37,7 +42,7 @@ 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
-- 
cgit 


From 1c9975a4c79a02569f92310cf5e30ccd2b542033 Mon Sep 17 00:00:00 2001
From: Abigail <abigail@abigail.be>
Date: Sat, 23 Jan 2021 21:44:49 +0100
Subject: Use 'distance' instead of 'distances' for the array name.

---
 challenge-096/abigail/lua/ch-2.lua | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

(limited to 'challenge-096/abigail/lua/ch-2.lua')

diff --git a/challenge-096/abigail/lua/ch-2.lua b/challenge-096/abigail/lua/ch-2.lua
index ef1b039579..99058213ca 100755
--- a/challenge-096/abigail/lua/ch-2.lua
+++ b/challenge-096/abigail/lua/ch-2.lua
@@ -17,13 +17,13 @@
 function LevenshteinDistance (first, second)
     local n = first  : len ()
     local m = second : len ()
-    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) ==
@@ -31,10 +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
@@ -46,10 +46,10 @@ function LevenshteinDistance (first, second)
         --
         if i > 0
         then
-            distances [i - 1] = nil
+            distance [i - 1] = nil
         end
     end
-    return distances [n] [m]
+    return distance [n] [m]
 end
 
 
-- 
cgit