JAVA:实现MinHeap最小堆算法(附完整源码)

下面是 Java 实现小根堆的完整源码，包括添加元素、删除堆顶元素、获取堆顶元素、获取堆大小等常用操作： ``` import java.util.Arrays; public class MinHeap { private int[] heap; private int size; public MinHeap(int capacity) { heap = new int[capacity]; } public void add(int value) { if (size >= heap.length) { heap = Arrays.copyOf(heap, size * 2); } heap[size] = value; size++; siftUp(size - 1); } public int remove() { int result = heap[0]; size--; heap[0] = heap[size]; siftDown(0); return result; } public int peek() { return heap[0]; } public int size() { return size; } private void siftUp(int index) { int parent = (index - 1) / 2; while (index > 0 && heap[index] < heap[parent]) { swap(index, parent); index = parent; parent = (index - 1) / 2; } } private void siftDown(int index) { int left = index * 2 + 1; int right = index * 2 + 2; int smallest = index; if (left < size && heap[left] < heap[smallest]) { smallest = left; } if (right < size && heap[right] < heap[smallest]) { smallest = right; } if (smallest != index) { swap(index, smallest); siftDown(smallest); } } private void swap(int i, int j) { int temp = heap[i]; heap[i] = heap[j]; heap[j] = temp; } } ``` 使用示例： ``` MinHeap heap = new MinHeap(5); heap.add(3); heap.add(1); heap.add(4); heap.add(2); heap.add(5); System.out.println(heap.remove()); // 输出 1 System.out.println(heap.peek()); // 输出 2 System.out.println(heap.size()); // 输出 4 ```