大顶堆 Java部分实现
转载自 https://blog.csdn.net/sunlei_secret/article/details/68486452
//java 大顶堆的简单实现 import java.util.Arrays; public class Heap{ public void heapSort(int[] num){ int n = num.length; for(int i = n/2;i>=0;i--){ //建堆,从n/2开始向上调整 adjustHeap(num, i, n); }
for(int j=n-1;j>=0;j--){ swap(num,0, j); //交换开始和最后位置上的数字 adjustHeap(num, 0, j); //交换之后再调整堆 } }
public void adjustHeap(int[] num,int s,int n){ //由于根节点编号是从0开始的,所以其左子树是2*i+1 for(int i=s;i<n;){ int max = i; if((2*i+1)<n&&num[2*i+1]>num[max]) max = 2*i+1; if((2*i+2)<n&&num[2*i+2]>num[max]) max = 2*i+2; if(max!=i){ swap(num,i,max); i=max; }else break; } }
public void swap(int[] num,int i,int j){ int tem = num[i]; num[i] = num[j]; num[j] = tem; }
public static void main(String[] args) { Heap heap = new Heap(); int[] num = new int[]{49,38,65,97,76,13,27,49}; heap.heapSort(num); System.out.println(Arrays.toString(num)); } }
posted on 2019-03-03 10:47 wait_for_you 阅读(682) 评论(0) 编辑 收藏 举报