1762. 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: [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.

class Solution {
    public int[] findBuildings(int[] heights) {
        List<Integer> result = new LinkedList<>();
        
        if (heights == null || heights.length == 0) {
            return new int[0];
        }
        
        result.add(heights.length - 1);
        int highest = heights[heights.length - 1];
        
        for (int i = heights.length - 2; i >= 0; i--) {
            if (heights[i] > highest) {
                result.add(0, i);
                highest = heights[i];
            }
        }
        
        return result.stream().mapToInt(i->i).toArray();
    }
}