合并排序（归并）

//////////////////////////////////////mergeSort.h////////////////////////////

#include <vector>
using std::vector;

class MergeSort
{
public:
 MergeSort(int);
 void sort();
 void displayElements()const;
private:
 int size;
 vector<int>data;
 void sortSubVector(int,int);
 void merge(int,int,int,int);
 void displaySubVector(int,int) const;
};

//////////////////////////////////////mergeSort.cpp////////////////////////////

#include "stdafx.h"
#include <iostream>
using std::cout;
using std::endl;

#include <vector>
using std::vector;

#include <cstdlib>
using std::rand;
using std::srand;

#include <ctime>
using std::time;

#include "MergeSort.h"

MergeSort::MergeSort(int vectorSize)
{
 size = (vectorSize>0? vectorSize:10);
 srand(time(0));
 for (int i = 0;i<size;i++)
 {
  data.push_back(10 + rand() %90);
 }
}

void MergeSort::sort()
{
 sortSubVector(0,size - 1);
}

void MergeSort::sortSubVector(int low, int high)
{
 if ((high - low)>=1)
 {
  int middle1 = (low + high)/2;
  int middle2 = middle1 + 1;
/*  cout<<"split:    ";
  displaySubVector(low,high);
  cout<<endl<<"        ";
  displaySubVector(low,middle1);
  cout<<endl<<"        ";
  displaySubVector(middle2,high);
  cout<<endl<<"        ";
*/
  sortSubVector(low,middle1);
  sortSubVector(middle2,high);
  
  merge(low,middle1,middle2,high);
 }
}

void MergeSort::merge(int left,int middle1,int middle2,int right)
{
 int leftIndex = left;
 int rightIndex = middle2;
 int combinedIndex = left;
 vector<int> combined(size);

/* cout<<"merge:     ";
 displaySubVector(left,middle1);
 cout<<endl<<"        ";
 displaySubVector(middle2,right);
 cout<<endl;
*/
 while (leftIndex <= middle1 && rightIndex <=right)
 {
  if (data[leftIndex] <= data[rightIndex])
  {
   combined[combinedIndex++] = data[leftIndex++];
  }
  else
   combined[combinedIndex++] = data[rightIndex++];
 }
 if (leftIndex ==middle2)
 {
  while (rightIndex<=right)
  {
   combined[combinedIndex++] = data[rightIndex++];
  }
 }
 else
 {
  while (leftIndex<= middle1)
  {
   combined[combinedIndex++] = data[leftIndex++];
  }
 }
 for (int i = left;i<=right;i++)
 {
  data[i] = combined[i];
 }
/* cout<<"        ";
 displaySubVector(left,right);
 cout<<endl<<endl;
*/
}

void  MergeSort::displaySubVector(int low,int high) const
{
 for (int i = 0;i< low;i++)
 {
  cout<<"     ";
 }
 for (int i = low;i<=high;i++)
 {
  cout<<"    "<<data[i];
 }
}
void MergeSort::displayElements()const
{
 displaySubVector(0,size - 1);
}

 

//////////////////////////测试文件/////////////

#include "mergeSort.h
int _tmain(int argc, _TCHAR* argv[])
{
 MergeSort sortVector(10);
 cout<<"unsorted vector:"<<endl;
sortVector.displayElements();

 cout<<endl<<endl;

 sortVector.sort();
 cout<<"sorted vector:"<<endl;

sortVector.displayElements();
 cout<<endl;

 return 0;
}