Merge remote-tracking branch 'upstream/master'

1 files changed, 42 insertions, 0 deletions

diff --git a/challenge-081/tyler-wardhaugh/lua/ch-1.lua b/challenge-081/tyler-wardhaugh/lua/ch-1.lua
new file mode 100755
index 0000000000..8203f05c74
--- /dev/null
+++ b/challenge-081/tyler-wardhaugh/lua/ch-1.lua
@@ -0,0 +1,42 @@
+#!/usr/bin/env lua
+
+local t1 = {}
+
+do
+  local lpeg = require'lpeg'
+  local P = lpeg.P
+  function t1.make_pat(s)
+    return P(s)
+  end
+end
+
+function t1.common_base_string(s1, s2)
+  -- ensure s1 is smaller or equal in length to s2
+  if s1:len() > s2:len() then
+    s1, s2 = s2, s1
+  end
+
+  local s2_len = s2:len()
+  local results, substring, part = {}
+  for i = 1,s2_len do
+    -- skip attempt if s2's length not evenly divisible by i
+    if s2_len % i ~= 0 then goto continue end
+
+    substring = s2:sub(1, s2_len // i)
+    part = t1.make_pat(substring)
+    if (part^i):match(s2) and (part^1 * -1):match(s1) then
+      table.insert(results, substring)
+    end
+    ::continue::
+  end
+
+  return results
+end
+
+function t1.run(args)
+  local S1, S2 = table.unpack(args, 1, 2)
+  local bases = t1.common_base_string(S1, S2)
+  print(table.concat(bases, " "))
+end
+
+return t1