How would I find this in a table?

[Earthraphobic2]

Hello, I am not really making a game right now or having problems or anything, just curious. How would I go about finding an ordered set of numbers in a table? For example

local table = {8,2,4,6}

while task.wait() do
table.insert(table,math.random(1,5))
end

If this kept running, and the table has 1, 2, 3 in order anytime, how would I go about checking this? For example 8, 2, 4, 6, 1, 2, 3. It has 1, 2, 3 in the table order, how would I check this? Thanks!

[PoolloverNathan]

Your table is named table. Need I tell you how bad of an idea that is? It overrides the global table, which means that your table will never grow. Here is your script with the code added and the table renamed:

local nums = {8,2,4,6}

while task.wait() do
    table.insert(nums, math.random(1,5))
    local found = table.find(nums, 1)
    if found and nums[found + 1] == 2 and nums[found + 2] == 3 then
        print("Found 1, 2, 3 starting at " .. found)
        break
    end
end

[samjay22 (Dev)]

You can solve this using the sliding window algorithm which runs in linear time as opposed to quadratic time. The solution listed above is O(n^2) which is decent but can be refined.

The algorithm works by making a window of sorts to start on an index and end on another index. Inside of that window we would check the starting index which will be 1 and our ending index which would be 3.

local arr = {8,9,2,3,1,2,3}
local start, windowEnd = 1, 1
local max = #arr
local foundIndices = {}

while end < max do
task.wait()
if arr[start] == 1 then
foundIndices[arr[start]] = start
windowEnd += 1
if arr[windowEnd] == arr[start] + 1 or arr[windowEnd] == arr[windowEnd] + 1 then
foundIndices[arr[windowEnd]] = windowEnd
if #foundIndices == 3 then 
break
end
else
foundIndices = {}
start += 1
windowEnd = start
end
end

[PoolloverNathan]

Please, for Pete’s sake, indent your code!

local arr = {8,9,2,3,1,2,3}
local start, windowEnd = 1, 1
local max = #arr
local foundIndices = {}

while end < max do
    task.wait()
    if arr[start] == 1 then
        foundIndices[arr[start]] = start
        windowEnd += 1
        if arr[windowEnd] == arr[start] + 1 or arr[windowEnd] == arr[windowEnd] + 1 then
            foundIndices[arr[windowEnd]] = windowEnd
            if #foundIndices == 3 then 
                break
            end
        else
            foundIndices = {}
            start += 1
            windowEnd = start
        end
    end
end

I need a new spacebar. (Yes, I indented that by hand. Yes, you missed an end.)

[samjay22 (Dev)]

Sorry, I was leaving the office, quick reply.

[PoolloverNathan]

I have notifications on.

30-Chars

[Earthraphobic2]

Hello, your code does not work:

It does not print Found 1, 2, 3 starting at …found.

[Earthraphobic2]

This is giving me a ton of errors. Should end at the top be true?

[PoolloverNathan]

Does this one look/do better? It also should be more efficient.

local nums = {8,2,4,6}

while task.wait() do
    table.insert(nums, math.random(1,5))
    local l = #nums
    print("[" .. l .. "] = " .. nums[l])
    if nums[l] == 3 and nums[l - 1] == 2 and nums[l - 2] == 1 then
        print("Found 1, 2, 3 starting at " .. found)
        break
    end
end

[Earthraphobic2]

Unkown global found, did you mean to change it to L? if so then ill change it real quick

[PoolloverNathan]

Where?

30-chars

[Earthraphobic2]

[PoolloverNathan]

oh, sorry

local nums = {8,2,4,6}

while task.wait() do
    table.insert(nums, math.random(1,5))
    local l = #nums
    print("[" .. l .. "] = " .. nums[l])
    if nums[l] == 3 and nums[l - 1] == 2 and nums[l - 2] == 1 then
        print("Found 1, 2, 3 starting at " .. l-2)
        break
    end
end

Why are you trying to do this again? This seems like an x-y problem.

[Earthraphobic2]

Just curious lol, might come in handy later down the line in my projects. Thanks so much though!

[PoolloverNathan]

You’re welcome! Let me know if you need anything else.