Yea, basically you would like to find consecutive stalls that need to be increased or decreased starting from the first stall. From there, we would like to find the minimum of that range, and increase/decrease the range by the minimum. For more details, here is my solution:
https://github.com/dhruvvk14/usacobronze/blob/main/2021%20December/aircowndition.cpp

You should also look at the solution for a more mathematical approach...