-- lua_workload.lua - mixed string builder + table churn

local N = tonumber(os.getenv("LUA_WORK_N")) or 500000

-- String builder (amortized)
local t = {}
for i = 1, N do
  t[#t+1] = tostring(i)
  if (i % 5) == 0 then t[#t+1] = "-" end
end
local s = table.concat(t)

-- Table churn (insert/remove)
local arr = {}
for i = 1, N do
  arr[i] = i * 3
end
local sum = 0
for i = 1, N, 3 do
  sum = sum + (arr[i] or 0)
  arr[i] = nil
end

print("len(s)=", #s, " sum=", sum)