1124. 表现良好的最长时间段

 1 int longestWPI(vector<int>& hours) {
 2     int size = hours.size();
 3     vector<int> vec(size+1 , 0);
 4     for (int i = 1; i <= size; i++)
 5     {
 6         if (hours[i - 1] > 8)
 7             vec[i] = vec[i - 1] + 1;
 8         else
 9             vec[i] = vec[i - 1] - 1;
10     }
11     stack<int> use;
12     for (int i = 0; i <= size ; i++)
13     {
14         if (use.empty() || vec[i] < vec[use.top()])
15             use.push(i);
16     }
17     int res = 0;
18     for (int i = size ; i > -1; i--)
19     {
20         while (!use.empty()&&vec[i] > vec[use.top()])
21         {
22             res = max(res, i - use.top());
23             use.pop();
24         }
25     }
26     return res;
27 }