学步园

快速排序C++实现如下：

#include <iostream>
using namespace std;
int partition(int *a, int i, int j)
{
  int pivot = a[i];
  while(i<j)
  {
    while(i<j&&a[j]>=pivot) j--;
    if(i<j) a[i++] = a[j];
    while(i<j&&a[i]<=pivot) i++;
    if(i<j) a[j--] = a[i];
  }
  a[i] = pivot;
  return i;
}
void quickSort(int *a, int low, int high)
{
  int pivot;
  if(low<high)
  {
    pivot = partition(a, low, high);
    quickSort(a, low, pivot-1);
    quickSort(a, pivot+1, high);
  }
}
int main()
{
  int n,a[100000];
  cin >> n;
  for(int i=0; i<n; i++)
  {
    cin >> a[i];
  }
  quickSort(a, 0, n-1);
  for(int i=0; i<n; i++)
    cout << a[i] << " ";
}