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local function is_safe(a)
local up = false
local down = false
local prev = nil
for i, number in ipairs(a) do
number = tonumber(number)
if prev == nil then
prev = number
goto continue
end
if down==false and up==false then
if number < prev then down = true
elseif number > prev then up = true
else return false end
end
if up then
if prev > number then return false end
local r=number-prev
if r~=1 and r~=2 and r~= 3 then return false end
prev = number
end
if down then
if number > prev then return false end
local r=prev-number
if r~=1 and r~=2 and r~= 3 then return false end
prev = number
end
::continue::
end
return true
end
local file = io.open("2-input.txt", "r")
local safe = 0
local safe_one_skip = 0
for line in file:lines() do
local numbers = line:gmatch("[^%s]+")
local numbers_arr = {}
for i in numbers do
table.insert(numbers_arr, i)
end
if is_safe(numbers_arr) then
safe = safe + 1
safe_one_skip = safe_one_skip + 1
else
for i=1, #numbers_arr do
local n = table.remove(numbers_arr, i)
if is_safe(numbers_arr) then
safe_one_skip = safe_one_skip + 1
break
end
table.insert(numbers_arr, i, n)
end
end
end
file:close()
print("puzzle 1:", safe)
print("puzzle 2:", safe_one_skip)
-- 490
-- 536
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