<p>Given an array of integers <code>temperatures</code> represents the daily temperatures, return <em>an array</em> <code>answer</code> <em>such that</em> <code>answer[i]</code> <em>is the number of days you have to wait after the</em> <code>i<sup>th</sup></code> <em>day to get a warmer temperature</em>. If there is no future day for which this is possible, keep <code>answer[i] == 0</code> instead.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> temperatures = [73,74,75,71,69,72,76,73]
<strong>Output:</strong> [1,1,4,2,1,1,0,0]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> temperatures = [30,40,50,60]
<strong>Output:</strong> [1,1,1,0]
</pre><p><strong class="example">Example 3:</strong></p>
<pre><strong>Input:</strong> temperatures = [30,60,90]
<strong>Output:</strong> [1,1,0]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;=&nbsp;temperatures.length &lt;= 10<sup>5</sup></code></li>
	<li><code>30 &lt;=&nbsp;temperatures[i] &lt;= 100</code></li>
</ul>

class Solution {
public:
    vector<int> dailyTemperatures(vector<int>& temperatures) {
        // t 73,74,75,71,69,72,76,73
        // v  1  1  4 2  1 1  0  0
        // s 75                      //人質的概念 要等後面的數比他大才能釋放
        // k 2                      //用來記錄人質位置
        //stack 先進後出
        stack<int>s,k;
        vector<int> v(temperatures.size(),0);
        for(int i=0;i<temperatures.size();i++){
            while(!s.empty()){//如果現在走的的數字比人質大 要做處理
                if(temperatures[i]>s.top()){
                    v[k.top()]=i-k.top();
                    k.pop();
                    s.pop();
                }
                else{
                    break;
                }
            }
            if(i==temperatures.size()-1){
                break;
            }
            if(temperatures[i+1]>temperatures[i]){
                v[i]=1;
            }
            else{//放人質
                s.push(temperatures[i]);
                k.push(i);
            }
        }
        return v;
    }
};
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