Lua solution for week 106, part 2

1 files changed, 41 insertions, 0 deletions

diff --git a/challenge-106/abigail/lua/ch-2.lua b/challenge-106/abigail/lua/ch-2.lua
new file mode 100644
index 0000000000..9ac554756d
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+++ b/challenge-106/abigail/lua/ch-2.lua
@@ -0,0 +1,41 @@
+#!/opt/local/bin/lua
+
+--
+-- See ../README.md
+--
+
+--
+-- Run as: lua ch-2.lua < input-file
+--
+
+-- 
+-- For explaination of the method below, see ../README.md
+--
+
+function long_division (numerator, denominator)
+    local BASE     = 10
+    local fraction = math . floor (numerator / denominator) .. "."
+    local position = fraction : len ()
+    local seen     = {}
+
+    numerator = numerator % denominator
+
+    while (not seen [numerator]) do
+        if   numerator == 0
+        then return (fraction)
+        end
+        seen [numerator] = position;
+        fraction  = fraction .. math . floor (BASE * numerator / denominator)
+        numerator =                           BASE * numerator % denominator
+        position  = position + 1
+    end
+
+    return (fraction : sub (1,  seen [numerator]) .. '(' ..
+            fraction : sub (1 + seen [numerator]) .. ')')
+
+end
+
+for line in io . lines () do
+    local _, _, numerator, denominator = line : find ("(%d+)%s+(%d+)")
+    print (long_division (numerator, denominator))
+end