left and right to represent the window's boundaries.sum to store the total number of fruits within the window.right pointer, adding the number of fruits at the current position to sum.left to right exceeds k steps, move the left pointer to the right, subtracting the number of fruits at the left position from sum.maxi if the current sum is greater.right pointer reaches the end of the array.maxi as the maximum total number of fruits that can be harvested.