Merge branch 'master' of github.com:seaker/perlweeklychallenge-club

2 files changed, 178 insertions, 0 deletions

diff --git a/challenge-101/abigail/lua/ch-1.lua b/challenge-101/abigail/lua/ch-1.lua
new file mode 100644
index 0000000000..23262855b3
--- /dev/null
+++ b/challenge-101/abigail/lua/ch-1.lua
@@ -0,0 +1,126 @@
+#!/opt/local/bin/lua
+
+--
+-- See ../README.md
+--
+
+--
+-- Run as: lua ch-1.lua < input-file
+--
+
+local RIGHT = 0
+local UP    = 1
+local LEFT  = 2
+local DOWN  = 3
+
+--
+-- Read in the input: a single line, with the elemens separated by white space
+--
+local line = io . read ()
+local elements = {}
+for element in line : gmatch ("%S+") do
+    elements [#elements + 1] = element
+end
+
+--
+-- Calculate the optimal width and height
+--
+local height = math . floor (math . sqrt (#elements))
+while #elements % height > 0 do
+    height = height - 1
+end
+local width = #elements / height
+
+--
+-- Fill the matrix, starting from the bottom left
+--
+local min_x     = 1
+local max_x     = height
+local min_y     = 1
+local max_y     = width
+local x         = max_x
+local y         = min_y
+local direction = RIGHT
+
+--
+-- Initialize the matrix
+--
+local matrix = {}
+for x = 1, height do
+    matrix [x] = {}
+end
+
+for i = 1, #elements do
+    matrix [x] [y] = elements [i]
+    local turn = 0
+
+    if   direction == RIGHT
+    then if   y >= max_y
+         then turn =  1
+              x = x - 1
+              max_x = max_x - 1
+         else y = y + 1
+         end
+    end
+
+    if   direction == UP
+    then if   x <= min_x
+         then turn =  1
+              y = y - 1
+              max_y = max_y - 1
+         else x = x - 1
+         end
+    end
+
+    if   direction == LEFT
+    then if   y <= min_y
+         then turn =  1
+              x = x + 1
+              min_x = min_x + 1
+         else y = y - 1
+         end
+    end
+
+    if   direction == DOWN
+    then if   x >= max_x
+         then turn =  1
+              y = y + 1
+              min_y = min_y + 1
+         else x = x + 1
+         end
+    end
+
+    if   turn > 0
+    then direction = (direction + 1) % 4
+    end
+
+end
+
+--
+-- Find the maximum widths in each column
+--
+local widths = {}
+for  y = 1, width
+do   local max = 0
+     for x = 1, height
+     do   if   max < #matrix [x] [y]
+          then max = #matrix [x] [y]
+          end
+     end
+     widths [y] = max
+end
+
+
+--
+-- Pretty print the matrix
+--
+for  x = 1, height
+do   for  y = 1, width
+     do   if   y > 1
+          then io . write (" ")
+          end
+          local format = "%" .. widths [y] .. "s"
+          io . write (string . format (format, matrix [x] [y]))
+     end
+     io . write ("\n")
+end
diff --git a/challenge-101/abigail/lua/ch-2.lua b/challenge-101/abigail/lua/ch-2.lua
new file mode 100644
index 0000000000..d7ecaacfb9
--- /dev/null
+++ b/challenge-101/abigail/lua/ch-2.lua
@@ -0,0 +1,52 @@
+#!/opt/local/bin/lua
+
+--
+-- See ../README.md
+--
+
+--
+-- Run as: lua ch-2.lua < input-file
+--
+
+--
+-- See ../README.md
+--
+
+--
+-- This determines on which side of the line through (x1, y1) and
+-- (x2, y2) the origin lies. If > 0, then the origin lies to the left
+-- of the line, if < 0, the origin lies to the right of the line, if
+-- = 0, the origin lies on the line.
+--
+function side (x1, y1, x2, y2)
+    return (y2 - y1) * x2 - (x2 - x1) * y2
+end
+
+for line in io . lines () do
+    --
+    -- Parse input
+    --
+    local _, _, x1, y1, x2, y2, x3, y3 =
+          line : find ("(%S+) (%S+) (%S+) (%S+) (%S+) (%S+)")
+
+    --
+    -- Determine where the origin is relative to the three lines 
+    -- through the vertices of the triangle. Note we have to go
+    -- in a specific order through the points. (Either clock wise,
+    -- or counter clockwise, as long as we're consistent).
+    --
+    local s1 = side (x2, y2, x3, y3)
+    local s2 = side (x3, y3, x1, y1)
+    local s3 = side (x1, y1, x2, y2)
+
+    --
+    -- If the origin either lies to the left (or on) each of the
+    -- lines, or to the right (or on) each of the lines, the origin
+    -- lies inside the triangle. If not, it does not.
+    --
+    if (s1 <= 0 and s2 <= 0 and s3 <= 0) or
+       (s1 >= 0 and s2 >= 0 and s3 >= 0)
+    then print (1)
+    else print (0)
+    end
+end