堆排序（Heapsort）是指利用堆这种数据结构所设计的一种排序算法。堆积是一个近似完全二叉树的结构，并同时满足堆积的性质：即子结点的键值或索引总是小于（或者大于）它的父节点。

通常堆是通过一维数组来实现的。在数组起始位置为0的情形中：

• 父节点i的左子节点在位置(2*i+1);
• 父节点i的右子节点在位置(2*i+2);
• 子节点i的父节点在位置floor((i-1)/2);

In computer science, heapsort is a comparison-based sorting algorithm. Heapsort can be thought of as an improved selection sort: like that algorithm, it divides its input into a sorted and an unsorted region, and it iteratively shrinks the unsorted region by extracting the largest element and moving that to the sorted region. The improvement consists of the use of a heap data structure rather than a linear-time search to find the maximum.