Merge pull request #12473 from Firedrake/rogerbw-challenge-333

RogerBW solutions for challenge no. 333

1 files changed, 70 insertions, 0 deletions

diff --git a/challenge-333/roger-bell-west/lua/ch-1.lua b/challenge-333/roger-bell-west/lua/ch-1.lua
new file mode 100755
index 0000000000..7a5ff61942
--- /dev/null
+++ b/challenge-333/roger-bell-west/lua/ch-1.lua
@@ -0,0 +1,70 @@
+#! /usr/bin/lua
+
+function straightline(a)
+   local b = {}
+   for _, xy in ipairs(a) do
+      local u = true
+      for __, bxy in ipairs(b) do
+         if xy[1] == bxy[1] and xy[2] == bxy[2] then
+            u = false
+            break
+         end
+      end
+      if u then
+         table.insert(b, xy)
+      end
+   end
+   if #b < 3 then
+      return true
+   end
+   local p = b[1][1]
+   local q = b[2][1] - b[1][1]
+   local r = b[1][2]
+   local s = b[2][2] - b[1][2]
+   for tp = 2, #b do
+      local tpair = b[tp]
+      if q == 0 and tpair[1] ~= b[1][1] then
+         return false
+      end
+      if s == 0 and tpair[2] ~= b[1][2] then
+         return false
+      end
+      if q ~= 0 and s ~= 0 then
+         local n1 = (tpair[1] - p) / q
+         local n2 = (tpair[2] - r) / s
+         if n1 ~= n2 then
+            return false
+         end
+      end
+   end
+   return true
+end
+
+if straightline({{2, 1}, {2, 3}, {2, 5}}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if straightline({{1, 4}, {3, 4}, {10, 4}}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if not straightline({{0, 0}, {1, 1}, {2, 3}}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if straightline({{1, 1}, {1, 1}, {1, 1}}) then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+