#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <stack>
#include <queue>
#include <malloc.h>
using namespace std;
#define OK 1
#define ERROR -1
#define TRUE 1
#define FALSE 0
typedef int Status;
//輸出函數(shù)
void Print(int a[], int l, int r)
{
 int i;
 for(i = l; i <= r; i++)
 {
  printf("%d ", a[i]);
 }
 printf("\n");
}
//劃分函數(shù)
int partion(int a[], int left, int right)
{
 //取最右邊的元素作劃分元素
 int temp = a[right];
 //記錄 i = left, j = right
 int i = left, j = right-1;
 //循環(huán)直到左右指針相遇
 while(true)
 {
  //從左邊開始掃描,當(dāng)出現(xiàn)比劃分元素大的元素,掃描停止
  while(temp > a[i])
  {
   i++;
  }
  //從右邊進(jìn)行掃描,當(dāng)出現(xiàn)比劃分元素小的元素,掃描停止
  while(temp < a[j] && j >= left)
  {
   j--;
  }
  //如果 i >= j, 循環(huán)截止,下面的交換不執(zhí)行
  if(i >= j) break;
  //交換停止時(shí)的元素
  swap(a[i], a[j]);
 }
 //交換該元素與劃分元素
 swap(a[i], a[right]);
 Print(a, 0, 6);
 //printf("i = %d", i);
 //劃分過程結(jié)束
 return i;
}
//快速排序
void qsort(int a[], int left, int right)
{
 //排序完成,循環(huán)截止
 if(right <= left)
  return;
 //做劃分
 int i = partion(a, left, right);
 //對(duì)左部分排序
 if(left < (i-1))
  printf("對(duì)%d~%d排序\n", left, i-1), qsort(a, left, i-1);
 //對(duì)右部分排序
 if(right > (i+1))
  printf("對(duì)%d~%d排序\n", i+1, right), qsort(a, i+1, right);
}
int main()
{
 int a[7] = {2, 5, 3, 7, 6, 1, 4};
 //快速排序
 printf("對(duì)0~6排序\n");
 qsort(a, 0, 6);
 Print(a, 0, 6);
 return 0;
}

void qsort(int a[], int left, int right)
{
 int i;
 //定義棧s
 stack<int> s;
 //先判斷棧是否為空
 while(!s.empty())
 {
  //若棧不為空,將棧中元素移出
  s.pop();
 }
 //將right入棧
 s.push(right);
 //將left入棧
 s.push(left);
 //while循環(huán),當(dāng)棧為空時(shí),循環(huán)結(jié)束
 while(!s.empty())
 {
  //元素left出棧
  left = s.top(), s.pop();
  //元素right出棧
  right = s.top(), s.pop();
  //判斷l(xiāng)eft與right的關(guān)系,如果left>=right,continue
  if(left >= right)
  {
   continue;
  }
  //作劃分
  i = partion(a, left, right);
  //比較兩個(gè)子數(shù)組的大小
  //將子數(shù)組中的較大者壓入棧
  if((i-1-left) > (right-i-1))
  {
   s.push(i-1);
   s.push(left);
   s.push(i+1);
   s.push(right);
  }
  else
  {
   s.push(i+1);
   s.push(right);
   s.push(i-1);
   s.push(left);
  }
 }
}