交换瓶子

/*

*说到定就是考快排

*/

import java.util.Scanner;

public class Main{
private static int count;
public static void main(String[] args)
{
Scanner in=new Scanner(System.in);
while(in.hasNext())
{
int n=in.nextInt();
int[] a=new int[n];
for(int i=0;i<n;i++)
a[i]=in.nextInt();
count=0;
quickSort(a,0,a.length-1);
System.out.println(count);
}
}
private static void quickSort(int[] a, int left, int right) {
// TODO Auto-generated method stub
if(left>=right)
return;
int povit=Partition(a,left,right);
quickSort(a,left,povit-1);
quickSort(a,povit+1,right);

}
private static int Partition(int[] a, int left, int right) {
// TODO Auto-generated method stub
int i=left,j=right;
while(i<j)
{
while(i<j &&a[i]<=a[j])
j--;
if(i<j)
{
int temp=a[i];
a[i]=a[j];
a[j]=temp;
count++;
}
while(i<j && a[i]<=a[j])
i++;
if(i<j)
{
int temp=a[i];
a[i]=a[j];
a[j]=temp;
}
}
return i;
}
}