poj2388

 一道水题,是用刚学的快速排序做的,代码如下:

 

 

#include<stdio.h>
int qkpass(int a[],int left,int right)
{
 int key,low,high;
 low=left;
 high=right;
 key=a[low];
    while(low<high)
 {
  while(low<high&&a[high]>=key)
   high--;
  if(low<high)
  {
   a[low]=a[high];
   low++;
  }
  while(low<high&&a[low]<=key)
   low++;
  if(low<high)
  {
   a[high]=a[low];
   high--;
  }
 }
 a[low]=key;
 return low;
}
void qksort(int a[],int low,int high)
{
 int pos;
 if(low<high)
 {
  pos=qkpass(a,low,high);
  qksort(a,low,pos-1);
  qksort(a,pos+1,high);
 }
}
int main()
{
 int i,n,a[10000];
 scanf("%d",&n);
 for(i=0;i<n;i++)
  scanf("%d",&a[i]);
 qksort(a,0,n-1);
 printf("%d",a[(n-1)/2]);
 return 0;
}