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 <= 1051 <= heights[i] <= 109struct Solution;
impl Solution {
fn find_buildings(heights: Vec<i32>) -> Vec<i32> {
let mut stack = vec![];
let n = heights.len();
for i in 0..n {
while let Some(&j) = stack.last() {
if heights[j] <= heights[i] {
stack.pop();
} else {
break;
}
}
stack.push(i);
}
stack.into_iter().map(|i| i as i32).collect()
}
}
#[test]
fn test() {
let heights = vec![4, 2, 3, 1];
let res = vec![0, 2, 3];
assert_eq!(Solution::find_buildings(heights), res);
let heights = vec![4, 3, 2, 1];
let res = vec![0, 1, 2, 3];
assert_eq!(Solution::find_buildings(heights), res);
let heights = vec![2, 2, 2, 2];
let res = vec![3];
assert_eq!(Solution::find_buildings(heights), res);
}