LeetCode 739

class Solution {
    public int[] dailyTemperatures(int[] tem) {
        int n = tem.length;
        int[] res = new int[n];
        // 维护了一个栈，栈中的元素是 t 后面的由按顺序且小到大序列[]
        Deque<Integer> stk = new LinkedList<>();
                
        for (int i = n - 1; i >= 0; i-- ) {
            int t = tem[i];
            int cnt = 0;
            while (!stk.isEmpty() && t >= tem[stk.peek()]) {
                stk.pop();
            }
            if (stk.isEmpty()) res[i] = 0;
            else res[i] = stk.peek() - i;
            stk.push(i);            
        }
        
        return res;
    }
}