In computer science, heapsort is a comparison-based sorting algorithm which can be thought of as "an implementation of selection sort using the right data structure."[3] Like selection sort, heapsort divides its input into a sorted and an unsorted region, and it iteratively shrinks the unsorted region by extracting the largest element from it and inserting it into the sorted region. Unlike selection sort, heapsort does not waste time with a linear-time scan of the unsorted region; rather, heap sort maintains the unsorted region in a heap data structure to efficiently find the largest element in each step. Although somewhat slower in practice on most machines than a well-implemented quicksort, it has the advantages of very simple implementation and a more favorable worst-case O(n log n) runtime. Most real-world quicksort variants include an implementation of heapsort as a fallback should they detect that quicksort is becoming degenerate. 【在计算机科学中，堆排序是一种基于比较的排序算法，可以将其视为“使用正确数据结构的选择排序的实现”。与选择排序一样，堆排序将其输入分为已排序区域和未排序区域， 它通过从中提取最大元素并将其插入已排序区域来迭代地缩小未排序区域。 与选择排序不同，堆排序不会浪费时间对未排序区域进行线性时间扫描； 相反，堆排序维护堆数据结构中的未排序区域，以有效地找到每个步骤中的最大元素。 虽然在大多数机器上实践中比实现良好的快速排序要慢一些，但它具有实现非常简单和更有利的最坏情况 O(nlogn) 运行时间的优点。 大多数现实世界的快速排序变体都包含堆排序的实现，作为它们检测到快速排序正在退化的后备方案。 堆排序是一种就地算法，但它不是一种稳定的排序。】