68 lines
1.5 KiB
Lua
68 lines
1.5 KiB
Lua
--Lua 5.4.2
|
|
local File = io.open("input.txt", "r")
|
|
|
|
if not File then
|
|
print("File not found")
|
|
return
|
|
end
|
|
|
|
local function IsReportSafe(Numbers)
|
|
local IsSafe = true
|
|
local LastSign = 0
|
|
local LastNumber
|
|
for _, Number in next, Numbers do
|
|
if not LastNumber then
|
|
LastNumber = Number
|
|
goto continue
|
|
end
|
|
local Difference = math.abs(Number - LastNumber)
|
|
if Difference > 3 or Difference == 0 then
|
|
IsSafe = false
|
|
break
|
|
end
|
|
local Sign = (Number - LastNumber) > 0 and 1 or -1
|
|
if LastSign == 0 then
|
|
LastSign = Sign
|
|
else
|
|
if Sign ~= LastSign then
|
|
IsSafe = false
|
|
break
|
|
end
|
|
end
|
|
LastNumber = Number
|
|
::continue::
|
|
end
|
|
return IsSafe
|
|
end
|
|
|
|
local function Clone(t) --surface level copy
|
|
local Cloned = {}
|
|
for Key, Value in next, t do
|
|
Cloned[Key] = Value
|
|
end
|
|
return Cloned
|
|
end
|
|
|
|
local SafeReports = 0
|
|
|
|
for Line in File:lines() do
|
|
local Numbers = {}
|
|
for Number in Line:gmatch("%d+") do
|
|
table.insert(Numbers, tonumber(Number))
|
|
end
|
|
if IsReportSafe(Numbers) then
|
|
SafeReports = SafeReports + 1
|
|
else
|
|
for Index = 1, #Numbers do
|
|
local NumbersCopy = Clone(Numbers) --yikes
|
|
table.remove(NumbersCopy, Index)
|
|
if IsReportSafe(NumbersCopy) then
|
|
SafeReports = SafeReports + 1
|
|
break
|
|
end
|
|
end
|
|
end
|
|
end
|
|
|
|
print("Safe reports:", SafeReports)
|