Let's assume that the width of the array is bigger than the height, otherwise, we will split in another direction.

Split the array into three parts: central column left side and right side.

Go through the central column and two neighbor columns and look for maximum.

If it's in the central column - this is our peak.

If it's on the left side, run this algorithm on subarray left_side + central_column.

If it's on the right side, run this algorithm on subarray right_side + central_column