java实现HeapSort

堆排序的java实现

package Test;

class HeapSorts{
    public int[] heapSort(int[] array){
        array = buildMaxHeap(array);
        for(int i=array.length-1;i>0;i--){
            int temp = array[0];
            array[0] = array[i];
            array[i] = temp;
            adjustDownToUp(array, 0,i);
          }
          return array;
    }
   //建立大堆
    private int[] buildMaxHeap(int[] array){
       for(int i=(array.length-2)/2;i>=0;i--){
          adjustDownToUp(array, i,array.length);
          }
        return array;
    }
  //从下向上进行向上调整
    private void adjustDownToUp(int[] array,int k,int length){
       int temp = array[k];
       for(int i=2*k+1; i<length-1; i=2*i+1){
          if(i<length && array[i]<array[i+1]){
             i++;
          }
          if(temp>=array[i]){
             break;
           }else{
                array[k] = array[i];
                k = i;
             }
         }
          array[k] = temp;
    }
    //对toString方法进行覆写
    public void toString(int[] array){
        for(int i=0;i<array.length;i++){
            System.out.print(array[i]+" ");
        }
    }
}


public class HeapSort {
    public static void main(String[] args) {
        //测试堆排序
        HeapSorts heapSorts = new HeapSorts();
        int[] arr = {17,78,56,43,21,9};
        heapSorts.toString(heapSorts.heapSort(arr));
    }
}

运行结果：