how to solve/optimise this CodeWar

[viral ermine]

local function jump_to_zero(arr)
  local count={}
  local steps={}
  for i=1,#arr do
    local number=arr[i]
    count[i]=number
    steps[i]=0
    local temp=number
    local digits_sum=0
    while temp>0 do
  for j=1,#tostring(temp) do
      digits_sum=digits_sum+tonumber(string.sub(tostring(temp),j,j)) 
      end
      temp=temp-digits_sum
      steps[i]=steps[i]+1
    end
  end
  return steps
end

return jump_to_zero``` 

link: https://www.codewars.com/kata/64cfc5f033adb608e2aaedef/train/lua/6897a8d5bcb22fb5b17820cf

Subtask 2: n ≤ 10 ^ 5
Subtask 3: n ≤ 10 ^ 6
Subtask 4: n ≤ 7 * 10 ^ 6

also tried using a while loop instead of the 2nd for loop but that would be even slower

[broken carbon]

Hey so I have tried to recreate it on my own, heres what I did:

local function jump_to_zero(arr)
    local result = {}
    
    for _, num in ipairs(arr) do
        local steps = 0
        local temp = 0
        local digits = {}
        
        while #digits > 1 or #digits == 0 do -- while the num is > 9 or the digits are not set
            digits = {}
            temp = 0
            for digit in         
tostring(num):gmatch(".") do -- retrieve digits
                table.insert(digits, tonumber(digit))
            end
            
            for i, digit in ipairs(digits) do -- sum of digits
                temp += digit
            end
            
            num -= temp
            steps += 1
        end
        
        table.insert(result, steps)
    end
    
    return result
end

It seems to pass all subtasks with ease

However I dont know if you have figured it out yet but there seems to be a problem with your code

local digits_sum=0
while temp>0 do
    for j=1,#tostring(temp) do
        digits_sum=digits_sum+tonumber(string.sub(tostring(temp),j,j)) 
    end
    temp=temp-digits_sum
    steps[i]=steps[i]+1
end

In this part, you never reset the digits_sum

so it just keeps adding on and on, which results in the result being much smaller than the actual result

For example while jump_to_zero(200000) = 9350, your function returns 123

I have also forgot to reset that value in my function while I was writing it lol

Other than that your function seems fine

[viral ermine]

Did you try submitting it on CodeWars? I fixed the problem you found but its still very unoptimised

I tried making a cache but I'm not sure what I'm doing wrong for it to STILL be slow

[broken carbon]

Well are you sure?

[wind gull]

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