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.
Constraints:
1 <= heights.length <= 105
1 <= heights[i] <= 109
java
public class Solution {
public int[] findBuildings(int[] heights) {
ArrayList<Integer> results = new ArrayList<Integer>();
if (heights == null || heights.length == 0) {
return new int[0]; // Return an empty array if input is null or empty
}
int highest_building = -1;
for (int i = heights.length - 1; i >= 0; i--) {
if (heights[i] > highest_building) {
highest_building = heights[i];
results.add(i); // 从右往左遍历,把最高的楼房存下来
}
}
// Convert the ArrayList<Integer> to int[] 这里要特别注意,Interger的arraylist到int的array要手动转换一下。
int[] resultArray = new int[results.size()];
int j = 0;
for (int i = results.size() - 1; i >=0; i--) {
resultArray[j] = results.get(i);
j++;
}
return resultArray;
}
}