Formatted question description: https://leetcode.ca/all/1762.html

# 1762. Buildings With an Ocean View

## Level

Medium

## Description

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:** [3]

**Explanation:** Only building 3 has an ocean view.

**Example 4:**

**Input:** heights = [2,2,2,2]

**Output:** [3]

**Explanation:** Buildings cannot see the ocean if there are buildings of the same height to its right.

**Constraints:**

`1 <= heights.length <= 10^5`

`1 <= heights[i] <= 10^9`

## Solution

For index `i`

where `0 <= i < n`

, the building at index `i`

has an ocean view if and only if for all `i < j < n`

, there is `heights[i] > heights[j]`

. Obviously, the building at index `n - 1`

has an ocean view.

Loop over `heights`

backwards and maintain the maximum height. For the building at index `i`

, if `heights[i]`

is greater than the maximum height, then the building has an ocean view. Update the maximum height using `heights[i]`

after determining whether the building at index `i`

has an ocean view.

Finally, return the indices of buildings that have an ocean view.

```
class Solution {
public int[] findBuildings(int[] heights) {
int length = heights.length;
boolean[] oceanView = new boolean[length];
int count = 0;
int maxHeight = 0;
for (int i = length - 1; i >= 0; i--) {
if (heights[i] > maxHeight) {
oceanView[i] = true;
count++;
}
maxHeight = Math.max(maxHeight, heights[i]);
}
int[] buildings = new int[count];
int index = 0;
for (int i = 0; i < length; i++) {
if (oceanView[i])
buildings[index++] = i;
}
return buildings;
}
}
```