So i am trying to solve this problem`` And this is the tutorial i am referring to.Also this is the code. And I am trying to do it by dynamic approach. But can anyone please explain me this part :

`            if (dp[i - 1][j] > dp[i][(j * 10 + arr[i]) % 8])` 
`                dp[i][(j * 10 + arr[i]) % 8] = dp[i - 1][j];` 
``  
`            // If we exclude the number from our combination` 
`            if (dp[i — 1][j] > dp[i][j])` 
`                dp[i][j] = dp[i — 1][j];` 

what is j * 10 + arr[i]) % 8 doing here?. what is j here?. It will be great if you could explain in details?

Thank you!