#! /usr/bin/lua

-- by Michael Anderson at
-- https://stackoverflow.com/questions/8722620/comparing-two-index-tables-by-index-value-in-lua
-- modified by Roger
function recursive_compare(t1,t2)
  -- Use usual comparison first.
  if t1==t2 then return true end
  -- We only support non-default behavior for tables
  if (type(t1)~="table") then return false end
  -- They better have the same metatables
  local mt1 = getmetatable(t1)
  local mt2 = getmetatable(t2)
  if( not recursive_compare(mt1,mt2) ) then return false end
  -- Build list of all keys
  local kk = {}
  for k1, _ in pairs(t1) do
     kk[k1] = true
  end
  for k2, _ in pairs(t2) do
     kk[k2] = true
  end
  -- Check each key that exists in at least one table
  for _, k in ipairs(kk) do
     if (not recursive_compare(t1[k], t2[k])) then
        return false
     end
  end
  return true
end

function twoofthree(a)
   local ct = {}
   for _i, iv in ipairs(a) do
      local i = {}
      for _j, jv in ipairs(iv) do
         i[jv] = true
      end
      for k, _v in pairs(i) do
         if ct[k] == nil then
            ct[k] = 1
         else
            ct[k] = ct[k] + 1
         end
      end
   end
   local out = {}
   for k, v in pairs(ct) do
      if v >= 2 then
         table.insert(out, k)
      end
   end
   table.sort(out)
   return out
end

if recursive_compare(twoofthree({{1, 1, 2, 4}, {2, 4}, {4}}), {2, 4}) then
  io.write("Pass")
else
  io.write("FAIL")
end
io.write(" ")

if recursive_compare(twoofthree({{4, 1}, {2, 4}, {1, 2}}), {1, 2, 4}) then
  io.write("Pass")
else
  io.write("FAIL")
end
print("")