解题思路：

class Solution {
    public int[] maxAltitude(int[] heights, int limit) {
        if(heights.length == 0 || limit == 0) return new int[0];
        Deque<Integer> deque = new LinkedList<>();
        int[] res = new int[heights.length - limit + 1];
        // 未形成窗口
        for(int i = 0; i < limit; i++) {
            while(!deque.isEmpty() && deque.peekLast() < heights[i])
                deque.removeLast();
            deque.addLast(heights[i]);
        }
        res[0] = deque.peekFirst();
        // 形成窗口后
        for(int i = limit; i < heights.length; i++) {
            if(deque.peekFirst() == heights[i - limit])
                deque.removeFirst();
            while(!deque.isEmpty() && deque.peekLast() < heights[i])
                deque.removeLast();
            deque.addLast(heights[i]);
            res[i - limit + 1] = deque.peekFirst();
        }
        return res;
    }
}