大顶堆
每个结点的值都大于或等于其左右孩子结点的值
小顶堆
每个结点的值都小于或等于其左右孩子结点的值
对比图
实现代码
public class HeapNode{ private int size;//堆大小 private int[] heap;//保存堆数组 //初始化堆 public HeapNode(int n) { heap = new int[n]; size = 0; } //小顶堆建堆 public void minInsert(int key){ int i = this.size; if (i==0) heap[0] = key; else { while (i>0 && heap[i/2]>key){ heap[i] = heap[i/2]; i = i/2; } heap[i] = key; } this.size++; } //大顶堆建堆 public void maxInsert(int key){ int i = this.size; if (i==0) heap[0] = key; else { while (i>0 && heap[i/2]<key){ heap[i] = heap[i/2]; i = i/2; } heap[i] = key; } this.size++; } //小顶堆删除 public int minDelete(){ if (this.size==0) return -1; int top = heap[0]; int last = heap[this.size-1]; heap[0] = last; this.size--; //堆化 minHeapify(0); return top; } //大顶堆删除 public int maxDelete(){ if (this.size==0) return -1; int top = heap[0]; int last = heap[this.size-1]; heap[0] = last; this.size--; //堆化 maxHeapify(0); return top; } //小顶堆化 public void minHeapify(int i){ int L = 2*i,R=2*i+1,min; if (L<=size && heap[L] < heap[i]) min = L; else min = i; if (R <= size && heap[R] < heap[min]) min = R; if (min!=i){ int t = heap[min]; heap[min] = heap[i]; heap[i] = t; minHeapify(min); } } //大顶堆化 public void maxHeapify(int i){ int L = 2*i,R=2*i+1,max; if (L<=size && heap[L] > heap[i]) max = L; else max = i; if (R <= size && heap[R] > heap[max]) max = R; if (max!=i){ int t = heap[max]; heap[max] = heap[i]; heap[i] = t; maxHeapify(max); } } //输出堆 public void print(){ for (int i = 0; i < this.size; i++) { System.out.print(heap[i]+" "); } System.out.println(); }}
测试
public class Heap { static int[] a = {5,3,6,4,2,1}; static int n = a.length; public static void main(String[] args){ HeapNode heapNode = new HeapNode(n); for (int i = 0; i < n; i++) { heapNode.maxInsert(a[i]); } heapNode.print(); for (int i = 0; i < n; i++) { int min = heapNode.maxDelete(); System.out.print("堆顶："+min+" 剩下堆元素："); heapNode.print(); } }}
结果
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