priority_queue<int,vector<int>,greater<int> > heap;
时间: 2023-12-17 17:02:50 浏览: 30
priority_queue<int,vector<int>,greater<int> > heap; 是一个定义小根堆的优先队列,它存储整数类型的元素,并按照从小到大的顺序进行排序。这意味着在这个小根堆中,最小的元素将位于队列的顶部,而较大的元素将放置在较低的位置。你可以使用这个优先队列来实现一些需要按照特定顺序处理元素的算法。
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priority_queue<PII,vector<PII>,greater<PII>heap;
这是一个定义了一个名为 `heap` 的小根堆(`priority_queue`),其中元素的类型为 `PII`(即 pair<int,int>),使用 `vector` 作为底层容器,并且使用 `greater<PII>` 作为比较器,表示按照 `PII` 的第一个元素从小到大排序。具体使用方法可以参考 C++ 的 STL 文档。
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq
This is a declaration of a priority queue in C++ that stores pairs of integers. The priority queue is implemented using a min-heap, which means that the smallest element will have the highest priority. The first integer in the pair is the priority and the second integer is the value.
The syntax for declaring a priority queue in C++ is:
priority_queue<data_type, container_type, comparison_function>
In this case, the data type is a pair of integers (pair<int, int>), the container type is a vector (vector<pair<int, int>>), and the comparison function is the default less-than operator (>).
However, in order to implement a min-heap, we need to use the greater-than operator (<) instead. So we pass greater<pair<int, int>> as the comparison function.
Overall, this priority queue will store pairs of integers in ascending order of their first element. If two pairs have the same first element, then they will be ordered based on their second element in ascending order as well.