解题思路：

单调栈

class Solution {public int[] dailyTemperatures(int[] temperatures) {int length = temperatures.length;int[] ans = new int[length];Deque<Integer> stack = new LinkedList<>();for (int i = 0; i < length; i++) {int temperature = temperatures[i];while (!stack.isEmpty() && temperature > temperatures[stack.peek()]) {int preIndex = stack.pop();ans[preIndex] = i - preIndex;}stack.push(i);}return ans;}
}