Implementing Heap Sort Algorithm in Java

Heap sort is an efficient sorting algorithm based on the heap data structure, with a time complexity of O(n log n) and a space complexity of O(1). It is an in-place sorting algorithm suitable for large-scale data. A heap is a special complete binary tree, divided into a max-heap (parent node value is greater than child node values) and a min-heap. Heap sort uses a max-heap. The core idea is: each time, take the maximum value at the top of the heap and place it at the end of the array, then adjust the remaining elements to form a new max-heap, and repeat until the array is sorted. The implementation consists of three steps: constructing a max-heap (starting from the last non-leaf node and using heapify to adjust each node); heap adjustment (recursively adjusting the subtree to maintain the max-heap property); and the sorting process (swapping the top of the heap with the end element, reducing the heap size, and repeating the adjustment). The core function heapify adjusts the subtree to a max-heap by comparing parent and child nodes recursively; buildMaxHeap constructs a complete max-heap starting from the second-to-last node; the main function integrates the above steps to complete the sorting. Heap sort achieves ordering through efficient heap adjustment, is suitable for scenarios with space constraints, and is an efficient choice for sorting large-scale data.