Java implementation of quick sorting QuickSort example

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Quick sort

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Thoughts

As shown above: At the beginning of each quick sort, set a key, key=array[ low], then go from high to the left, find the value that is less than the key, copy it to the low position, then go from low to the right to find the value that is greater than the key, copy it to the high position, until the end of low=high,

will The key is copied to the low position.

In the above figure, after the first round of division, the position of 32 is found, and then the left and right sides of 32 are sorted recursively.

Code:

package Sort;
import java.util.Arrays;
public class QuickSort {

 public static void main(String[] args) {
  int array[]={32, 12, 7, 78, 23, 45};
  quickSort(array,0,array.length-1);
  System.out.println(Arrays.toString(array));
 }
 public static void quickSort(int array[],int left,int right)
 {
  if(left>=right)
  {
   return ;
  }
  int i=left;
  int j=right;
  int key=array[left];
  while(i<j)
  {
   while(i<j&&array[j]>key)
   {
    j--;
   }
   array[i]=array[j];
   //从后往前找到第一个比key小的数与array[i]交换；
   while(i<j&&array[i]<key)
   {
    i++;
   }
   array[j]=array[i];
   //从前往后找到第一个比key大的数与array[j]交换；
  }
  array[i]=key;
  //一趟快排之后已经将key的位置找到。
  quickSort(array,left,i-1);
  //对key左边的进行排序
  quickSort(array,i+1,right);
  //对key右边的进行排序
 }
}

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