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local dbg = require("debugger")
local f
if (arg[1]) then
f = assert(io.open(arg[1], "r"))
else
f = io.stdin
end
WIDTH = 10000
local nodes = {}
local minx, miny, maxx, maxy
function printgrid()
for y=miny-5,maxy do
for x=minx,maxx do
i = nodes[x *WIDTH + y]
io.write(i == 1 and "#" or i == 2 and "+" or i == 3 and "@" or ".")
end
io.write("\n")
end
end
for line in f:lines() do
local prev = nil
for x,y in line:gmatch("(%d+),(%d+)") do
x = tonumber(x)
y = tonumber(y)
minx = math.min(x, minx and minx or x)
maxx = math.max(x, maxx and maxx or x)
miny = math.min(y, miny and miny or y)
maxy = math.max(y, maxy and maxy or y)
if (prev) then
for i = prev.x,x,(prev.x < x and 1 or -1) do
for j = prev.y,y,(prev.y < y and 1 or -1) do
nodes[i*WIDTH + j] = 1
end
end
end
nodes[x *WIDTH + y] = 1
prev = {x=x,y=y};
end
end
function isempty(x, y)
return (not nodes[x*WIDTH + y] and y < maxy+2) and {x,y} or false
end
local cntr = 0
local x,y = 500,0
while 1 do -- new grains coming in
--local x, y = 500, 0
x, y = 500, 0
while 1 do -- path of each grain
local xy = isempty(x, y+1) or isempty(x-1, y+1) or isempty(x+1, y+1) or nil
if xy == nil then break end
x, y = xy[1], xy[2]
if y > maxy then break end
end
nodes[x *WIDTH + y] = 2
if y > maxy then
break
end
cntr = cntr + 1
end
print(cntr)
-- don't reset cntr or reset nodes.
while 1 do
x, y = 500, 0
while 1 do
local xy = isempty(x, y+1) or isempty(x-1, y+1) or isempty(x+1, y+1) or nil
if xy == nil then break end
x, y = xy[1], xy[2]
if y == 0 and x == 500 then break end
end
nodes[x *WIDTH + y] = 2
if y == 0 and x == 500 then break end
cntr = cntr + 1
end
print(cntr+2) -- +2 for the two we missed after
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