--[[
io.input("test")
local targetRow = 10
local maxx, maxy = 20, 20
--]]
--[
io.input("input")
local targetRow = 2000000
local maxx, maxy = 4000000, 4000000
--]]

function abs(x)
  return (x>=0) and x or -x
end

function distance(x1, y1, x2, y2)
  return abs(x1-x2) + abs(y1-y2)
end

function inRange( x, y, row, targetD )
  local startD = abs(row-y)
  local dif = targetD - startD
  if dif<0 then return nil
  else return x-dif, x+dif
  end
end

local count = 0
local positions = {}
local beacons = {} -- beacons in row
local data = {}
for line in io.lines() do
  local nums = {}
  for match in string.gmatch(line, "(-?%d+)") do
    table.insert( nums, tonumber(match) )
  end
  local sx, sy, bx, by = table.unpack(nums)
  local d = distance(sx, sy, bx, by)

  local r1, r2 = inRange(sx, sy, targetRow, d)
 -- print(sx, sy, bx, by, d)
  if r1 then
    for c = r1,r2 do
      positions[c] = true
    end
  end
  if by == targetRow then
    beacons[bx] = true
  end

  -- for part 2
  table.insert(data, {sx, sy, bx, by, d})
end

local result1 = 0
local min, max = math.maxinteger, math.mininteger
for x,v in pairs(positions) do
--  print(x, v)
  if not beacons[x] then
    result1 = result1 + 1
  end
end

print("part 1", result1)



-- part 2

function join( r1, r2 )
  local mini = (r1.i < r2.i ) and r1.i or r2.i
  local maxf = (r1.f > r2.f ) and r1.f or r2.f
  if r2.i <= r1.f+1 and r1.i<=r2.i or r1.i <= r2.f+1 and r2.i <= r1.i then
    return { i = mini, f = maxf }
  else
    return r1, r2
  end
end

--[[
function cleanUp( ranges )
  local i = 2
  repeat 
    local r1, r2 = join( ranges[i], ranges[i-1] )
    if not r2 then
      ranges[i-1] = r1 -- joined range
      table.remove( ranges, i )
    else -- don't intersect, try again
      i = i + 1
    end
  until i > #ranges
end
--]]


local found = false
local minx, miny = 0, 0
local beaconX, beaconY
for y = miny, maxy do 
  if y%500000==0 then print("#"..tostring(y)) end
--  print("#"..tostring(y))
  local ranges = {}
  local beacons = {} -- beacons in row
  for _, t in ipairs(data) do
    local sx, sy, bx, by, d = table.unpack(t)
    local ri, rf = inRange(sx, sy, y, d)
    if ri then
      ri = (ri > minx) and ri or minx 
      rf = (rf < maxx) and rf or maxx
      local range = { i=ri, f=rf }
      if #ranges == 0 then
        table.insert( ranges, range )
      else
        local i = 1
        repeat 
          local done
          local r1, r2 = join( ranges[i], range )
          if not r2 then
            ranges[i] = r1 -- joined range
            done = true
          else -- don't intersect, try again
            i = i + 1
            -- unless there are no more
            if i > #ranges then 
              ranges[i] = range
              done = true
            end
          end
        until done
      end

    end
  end

  if #ranges > 1 then
  -- clean up
    local i = 2
    repeat 
      local r1, r2 = join( ranges[i], ranges[i-1] )
      if not r2 then
        ranges[i-1] = r1 -- joined range
        table.remove( ranges, i )
      else -- don't intersect, try again
        i = i + 1
      end
    until i > #ranges
  end

  -- if there are still two ranges, here's the answer
  if #ranges > 1 then
    local r1, r2 = ranges[1], ranges[2]
    local minf = (r1.f>r2.f) and r2.f or r1.f
    beaconX = minf+1
    beaconY = y
  end
    
  if beaconX then break end
end

local result2 = beaconX*4000000 + beaconY
print("part 2", result2)
print(beaconX, beaconY)
-- part 2	12518502636475
-- 3129625	2636475