伪最大堆顶堆排序--没有真正理解最大堆

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伪最大堆排序HeapSort：

1、在这个排序中只想到把最大的值放到堆顶，没有注意到最大堆的定义：最大堆的任意子树中的根节点不小于该子树的子节点；

public class HeapSortCopy {
   private static int num = 0;//循环次数

   public int[] sort(int[] forSort,int lenght){
       if (forSort == null || lenght <= 1) {
            return forSort;
        }
       while(lenght>1){
           for(int i=lenght/2-1;i>=0;i--){
               num++;
               int largest = i ;
               if(2*i+1<=lenght-1 && forSort[i] < forSort[2*i+1]){
                   largest = 2*i + 1;
               }
               if(2*i+2<=lenght-1 && forSort[largest] < forSort[2*i+2]){
                   largest = 2*i+2;
               }
                //System.out.println("分次结果："+Arrays.toString(forSort) +",i="+i);
               if(largest != i) swap(forSort,i,largest);
           }
           swap(forSort,0,lenght-1);
           lenght--;
//           sort(forSort, lenght);
       }
       return forSort;
   }

   private void swap(int[] forSort,int i, int j) {
       int temp = forSort[i];
       forSort[i] = forSort[j];
       forSort[j] = temp;
   }

   public static void main(String[] args) {
//       int[] array = {2,5,6,8,5,4,6,9,4,9};
      int[] array = {2,5,6,8,5,4,6,9,4,9,-4,-6,45,54,67,0,8,4,-3,5,-23,-45,30};
       HeapSortCopy heapSort = new HeapSortCopy();
       long begintime = System.currentTimeMillis();
       heapSort.sort(array, array.length);
       long endtime = System.currentTimeMillis();
       System.out.println("最终结果："+Arrays.toString(array)+",num="+num);

   }
}

执行结果：

最终结果：[-45, -23, -6, -4, -3, 0, 2, 4, 4, 4, 5, 5, 5, 6, 6, 8, 8, 9, 9, 30, 45, 54, 67],num=132

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