I have a 2d array. I need to perform a few operations on it as fast as possible (function will be called a dozen of times per second, so It would be nice to make it efficient).

Now, let's say I want to get element `A[i][j]`, is there any difference in speed between simply using `A[i][j]` and `*(A+(i*width+j))` (ignoring the fact that I need to calculate i\*width+j, let's say I already have this value)?