#! /usr/bin/lua

function arraysintersection(a)
   local s = {}
   for _, x in ipairs(a[1]) do
      s[x] = true
   end
   for bi = 2, #a do
      local intersect = {}
      for _, x in ipairs(a[bi]) do
         if s[x] ~= nil then
            intersect[x] = true
         end
      end
      s = intersect
   end
   local o = {}
   for k, _ in pairs(s) do
      table.insert(o, k)
   end
   table.sort(o, function (i, j) return i < j end)
   return o
end

-- 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

if recursive_compare(arraysintersection({{1, 2, 3, 4}, {4, 5, 6, 1}, {4, 2, 1, 3}}), {1, 4}) then
  io.write("Pass")
else
  io.write("FAIL")
end
io.write(" ")

if recursive_compare(arraysintersection({{1, 0, 2, 3}, {2, 4, 5}}), {2}) then
  io.write("Pass")
else
  io.write("FAIL")
end
io.write(" ")

if recursive_compare(arraysintersection({{1, 2, 3}, {4, 5}, {6}}), {}) then
  io.write("Pass")
else
  io.write("FAIL")
end
print("")