# LeetCode 1762. Buildings With an Ocean View

## Description

https://leetcode.com/problems/buildings-with-an-ocean-view/

There are `n` buildings in a line. You are given an integer array `heights` of size `n` that represents the heights of the buildings in the line.

The ocean is to the right of the buildings. A building has an ocean view if the building can see the ocean without obstructions. Formally, a building has an ocean view if all the buildings to its right have a smaller height.

Return a list of indices (0-indexed) of buildings that have an ocean view, sorted in increasing order.

Example 1:

```Input: heights = [4,2,3,1]
Output: [0,2,3]
Explanation: Building 1 (0-indexed) does not have an ocean view because building 2 is taller.
```

Example 2:

```Input: heights = [4,3,2,1]
Output: [0,1,2,3]
Explanation: All the buildings have an ocean view.```

Example 3:

```Input: heights = [1,3,2,4]
Output: 
Explanation: Only building 3 has an ocean view.```

Example 4:

```Input: heights = [2,2,2,2]
Output: 
Explanation: Buildings cannot see the ocean if there are buildings of the same height to its right.```

Constraints:

• `1 <= heights.length <= 105`
• `1 <= heights[i] <= 109`

## Explanation

Iterate from the right side and keep tracking of the tallest height. If a building is greater than the tallest height, append it to the ocean view buildings.

## Python Solution

``````class Solution:
def findBuildings(self, heights: List[int]) -> List[int]:
results = []

prev_max = None

for i in range(len(heights) - 1, -1, -1):
height = heights[i]

if not prev_max:
prev_max = height
results.append(i)
else:
if height > prev_max:
results.append(i)
prev_max = max(prev_max, height)

return sorted(results)``````
• Time Complexity: O(Nlog(N)).
• Space Complexity: O(N).