qsort1.c

来自「自己做的常用库和实现的数据结构。public domain.」· C语言 代码 · 共 307 行

  #include   "stdafx.h"

#include <iostream.h>

#include <stack.h>

 

#define MAX_SIZE      10

using namespace std;

 

typedef int elem;

typedef std::stack<int> Stack;

 

int partition(elem *pData, int low, int high);

void swap(elem& a, elem& b);

void qsort(elem* pData, int low, int high);

void qsort2(elem* pData, int low, int high);

void qsort3(elem* pData, int low, int high);

 

int partition(elem *pData, int low, int high)

{

       elem key = pData[low];

 

       while(low < high)

       {

              while(low < high && pData[high] >= key)

                     high--;

 

              swap(pData[low], pData[high]);

 

              while(low < high && pData[low] <= key)

                     low++;

 

              swap(pData[low], pData[high]);

       }

 

       return low;

}

 

void swap(elem& a, elem& b)

{

       if(&a != &b)

       {

              a ^= b;

              b ^= a;

              a ^= b;

       }

 

}


//这个是原始的算法 

void qsort(elem* pData, int low, int high)

{

       if(low < high)

       {

              int pivot = partition(pData, low, high);

              qsort(pData, low, pivot - 1);

              qsort(pData, pivot + 1, high);

       }

}


//这个是第一次转化成递归以后的算法

void qsort2(elem* pData, int low, int high)

{

       Stack st;

 

       if(low < high)

       {

              int pivot = partition(pData, low, high);

              st.push(low);

              st.push(pivot - 1);

 

              st.push(pivot + 1);

              st.push(high);

             

              while(!st.empty())

              {

                     high = st.top();

                     st.pop();

                     low = st.top();

                     st.pop();

                    

                     pivot = partition(pData, low, high);

                    

                     if(low < high)

                     {

                            st.push(low);

                            st.push(pivot - 1);

 

                            st.push(pivot + 1);

                            st.push(high);

                     }

              }

       }

}


//这个是转化成递归以后改进的算法
void qsort3(elem* pData, int low, int high)

{

       Stack st;

       int tmp;

 

       if(low < high)

       {

              int pivot = partition(pData, low, high);

              st.push(low);

              st.push(pivot - 1);

 

              st.push(pivot + 1);

              st.push(high);

             

              while(!st.empty())

              {

                     high = st.top();

                     st.pop();

                     low = st.top();

                     st.pop();

                    

                     if(low < high)

                     {

                            pivot = partition(pData, low, high);

                           

                            tmp = pivot - 1;

                            if(low < tmp)

                            {

                                   st.push(low);

                                   st.push(tmp);

                            }

 

                            tmp = pivot + 1;

                            if(tmp < high)

                            {

                                   st.push(tmp);

                                   st.push(high);

                            }

                     }

              }

       }

}

 

//测试代码
int _tmain(int argc, _TCHAR* argv[])

{

      

       elem data[MAX_SIZE] = {12, 1, 13, 14, 67, 23, 12, 3, 90, 76};

       //qsort(data, 0, MAX_SIZE - 1);

       //qsort2(data, 0, MAX_SIZE - 1);

       qsort3(data, 0, MAX_SIZE - 1);

      

       for(int i=0; i< MAX_SIZE; i++)

       {

              cout << data[i] << " ";

       }

 

       cout << endl;

      

       cin.get();

       return 0;

}