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local function parse_instruction (x, y, dont)
if dont then return 'dont'
elseif x then return {'mul', tonumber(x), tonumber(y)}
else return 'do'
end
end
local function input ()
local line = ''
local start, next_mul, next_do = 1, 0, 0
return function ()
while true do
if next_mul and next_mul < start then
next_mul = string.find(line, 'mul', start)
end
if next_do and next_do < start then
next_do = string.find(line, 'do', start)
end
if next_mul and (not next_do or next_mul < next_do) then
start = next_mul + 1
local x, y = string.match(line, '^mul%((%d+),(%d+)%)', next_mul)
if x then return 'mul', tonumber(x), tonumber(y) end
elseif next_do and (not next_mul or next_do < next_mul) then
start = next_do + 1
if string.match(line, '^do%(%)', next_do) then
return 'do'
elseif string.match(line, "^don't%(%)", next_do) then
return 'dont'
end
elseif not next_mul and not next_do then
line = io.read '*l'
if not line then return end
start, next_mul, next_do = 1, 0, 0
end
end
end
end
local funcs = {reader = input()}
function funcs:part1 ()
local sum = 0
for op, arg1, arg2 in self.reader do
if op == 'mul' then sum = sum + arg1 * arg2 end
end
print(sum)
end
function funcs:part2()
local sum = 0
local enabled = true
for op, arg1, arg2 in self.reader do
print(op, arg1, arg2)
if op == 'do' then
enabled = true
elseif op == 'dont' then
enabled = false
elseif op == 'mul' then
if enabled then sum = sum + arg1 * arg2 end
end
end
print(sum)
end
return funcs
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