function binner(limits, data)
  local bins = setmetatable({}, {__index=function() return 0 end})
  local n, flr = #limits+1, math.floor
  for _, x in ipairs(data) do
    local lo, hi = 1, n
    while lo < hi do 
      local mid = flr((lo + hi) / 2)
      if not limits[mid] or x < limits[mid] then hi=mid else lo=mid+1 end
    end
    bins[lo] = bins[lo] + 1
  end
  return bins
end

function printer(limits, bins)
  for i = 1, #limits+1 do
    print(string.format("[%3s,%3s):%d", limits[i-1] or " -", limits[i] or " +", bins[i]))
  end
end

print("PART 1:")
limits = {23, 37, 43, 53, 67, 83}
data = {95,21,94,12,99,4,70,75,83,93,52,80,57,5,53,86,65,17,92,83,71,61,54,58,47,
        16, 8, 9,32,84,7,87,46,19,30,37,96,6,98,40,79,97,45,64,60,29,49,36,43,55}
bins = binner(limits, data)
printer(limits, bins)

print("\nPART 2:")          
limits = {14, 18, 249, 312, 389, 392, 513, 591, 634, 720}
data = {445,814,519,697,700,130,255,889,481,122,932, 77,323,525,570,219,367,523,442,933,
        416,589,930,373,202,253,775, 47,731,685,293,126,133,450,545,100,741,583,763,306,
        655,267,248,477,549,238, 62,678, 98,534,622,907,406,714,184,391,913, 42,560,247,
        346,860, 56,138,546, 38,985,948, 58,213,799,319,390,634,458,945,733,507,916,123,
        345,110,720,917,313,845,426,  9,457,628,410,723,354,895,881,953,677,137,397, 97,
        854,740, 83,216,421, 94,517,479,292,963,376,981,480, 39,257,272,157,  5,316,395,
        787,942,456,242,759,898,576, 67,298,425,894,435,831,241,989,614,987,770,384,692,
        698,765,331,487,251,600,879,342,982,527,736,795,585, 40, 54,901,408,359,577,237,
        605,847,353,968,832,205,838,427,876,959,686,646,835,127,621,892,443,198,988,791,
        466, 23,707,467, 33,670,921,180,991,396,160,436,717,918,  8,374,101,684,727,749}
bins = binner(limits, data)
printer(limits, bins)