noip2007复赛提高组第一题答案

#include<stdio.h>
#include<string.h>
#define LEN 200000

int a[LEN],temp,mid;

int sort(int *a,int low,int high) //一趟快排
{

mid=a[low];
while (low<high)
{
while (low<high && a[high]>=mid) high--;
temp=a[low];a[low]=a[high];a[high]=temp;
while (low<high && a[high]<=mid) low++;
temp=a[low];a[low]=a[high];a[high]=temp;
}
return low;
}

void quicksort(int *a,int low,int high) //快排递归
{
//int mid;
if (low < high)
{
mid=sort(a,low,high);
quicksort(a,low,mid-1);
quicksort(a,mid+1,high);
}
}

int main()
{
FILE *fp;
int i,j,n,sum;

fp=fopen("count.in","r");
fscanf(fp,"%d",&n);
for (i=0;i<n;i++)
fscanf(fp,"%d",&a[i]);