Replace for loop with formula
- by hamax
I have this loop that runs in O(end - start) and I would like to replace it with something O(1).
If "width" wouldn't be decreasing, it would be pretty simple.
for (int i = start; i <= end; i++, width--)
if (i % 3 > 0) // 1 or 2, but not 0
z += width;
start, end and width have positive values
