排序算法整理

/*
 
 交换排序:	冒泡			快排
 插入排序:	直接插入排序	shell排序
 选择排序:	直接选择排序  堆排序
 归并排序
 附：
 排序算法原理：http://zh.wikipedia.org/wiki/Category:%E6%8E%92%E5%BA%8F%E7%AE%97%E6%B3%95
 flash演示: http://www.tyut.edu.cn/kecheng1/site01/suanfayanshi/list.asp?id=7
*/

#include <iostream>
#include <string>
using namespace std;

/*				冒泡法
	左右元素相比，往后冒泡
*/
template<typename T>
void BubbleSort(T* r, int n)
{
	T temp;
	int i,j;
	for (i=0;i<n-1;i++)
	{
		for (j=0;j<n-i-1;j++)
		{
			if (r[j] > r[j+1])
			{
				temp = r[j];
				r[j] = r[j+1];
				r[j+1] = temp;
			}
		}
	}
}

/*快速排序
左边比他小，右边比他大，每次得到一个最左边数据的位置*/
template<typename T>
void QuickSort(T a[],int low,int high)
{
	if(low < high)
	{
		T elem = a[low];
		int l = low, r = high;
		while(l < r)
		{	
			while(l < r && a[r] >= elem) r--;
			if (l < r)
			{
				a[l++] = a[r];
			}
			while(l< r && a[l] <= elem) l++;
			if (l < r)
			{
				a[r--] = a[l];
			}
		}
		a[r] = elem;
		QuickSort(a,low,r-1);
		QuickSort(a,r+1,high);
	}
}

/*插入排序
向右移，a[j+1]=a[j]*/
template<typename T>
void insert_sort(T a[],int n)
{
	int i,j;
	T elem;
	for (i= 1;i<n ;++i)
	{
		j = i- 1;
		elem = a[i];
		while(j>=0 && elem < a[j] )
		{
			a[j+1] = a[j]; j--;
		}
		a[j+1] = elem;
	}
	
}

/*希尔（shell）排序
把插入排序的改成d即可*/
template<typename T>
void shell_insert(T array[],int d,int len)
{    
	int i,j;
    T elem;
	for ( i = d;i < len;i++)    
	{       
		j = i - d;
		elem = array[i];                        
		while (j >= 0 && elem < array[j])         
		{                
			array[j+d] = array[j];                
			j = j - d;            
		}           
		array[j+d] = elem;             
	}
}

template<typename T>
void shell_sort(T array[],int len)
{    
	int inc = len;    
	do     
	{        
		inc = inc/2;        
		shell_insert(array,inc,len);    
	} 
	while (inc > 1);
}

/*选择排序
逐一比较，最小的放前面*/
template <typename T>
void SelectSort(T a[],int n)
{
	int i,j,elemNum;
	T elem;
	for (i=0;i<n-1;i++)
	{
		elemNum = i;
		for (j= i+1;j<n;j++)
		{
			if (a[j] < a[elemNum])
			{
				elemNum = j;
			}
		}
		if (elemNum != i)
		{
			elem = a[i];
			a[i] = a[elemNum];
			a[elemNum] = elem;
			
		}
		
	}
}

/*堆排序
a[s]>=a[2*s] && a[s]>=a[2*s+1]*/
template<typename T>
void Max_heap(T a[],int S,int len)
{
	int l = 2*S;
	int r = 2*S+1;
	int maxI = S;
	T elem;
	if (l < len && a[l] > a[maxI])
	{
		maxI = l;
	}
	if (r < len && a[r] > a[maxI])
	{
		maxI = r;
	}
	if (maxI != S)
	{
		elem = a[S];
		a[S] = a[maxI];
		a[maxI] = elem;
		Max_heap(a,maxI,len);
	}
}

template<typename T>
void HeapSort(T a[],int n)
{
	int i;
	T elem;
	for (i = n/2;i>=0;i--)
	{
		Max_heap(a,i,n);
	}
	for (i= n-1;i>=1;i--)
	{
		elem = a[0];
		a[0] = a[i];
		a[i] = elem;
		n = n-1;
		Max_heap(a,0,n);
	}
}

/*归并排序
左边小左边，左边++；右边小取右边，右边++*/
template<typename T>
void merge(T array[], int low, int mid, int high)
{
	int k;
	T *temp = new T[high-low+1]; //申请空间，使其大小为两个已经排序序列之和，该空间用来存放合并后的序列
	int begin1 = low;
	int end1 = mid;
	int begin2 = mid + 1;
	int end2 = high;
	
	for (k = 0; begin1 <= end1 && begin2 <= end2; ++k)  //比较两个指针所指向的元素，选择相对小的元素放入到合并空间，并移动指针到下一位置
	{
		if(array[begin1]<=array[begin2])
			temp[k] = array[begin1++];
		else
			temp[k] = array[begin2++];   
	}
		
    if(begin1 <= end1) //若第一个序列有剩余，直接拷贝出来粘到合并序列尾
		memcpy(temp+k, array+begin1, (end1-begin1+1)*sizeof(T));
    if(begin2 <= end2) //若第二个序列有剩余，直接拷贝出来粘到合并序列尾
		memcpy(temp+k, array+begin2, (end2-begin2+1)*sizeof(T));
    memcpy(array+low, temp, (high-low+1)*sizeof(T));//将排序好的序列拷贝回数组中

    delete temp;
}

template<typename T>
void merge_sort(T array[], unsigned int first, unsigned int last)
{
	int mid = 0;
	if(first<last)
	{
		//mid = (first+last)/2; /*注意防止溢出*/
		mid = first/2 + last/2;
		//mid = (first & last) + ((first ^ last) >> 1);
		merge_sort(array, first, mid);
		merge_sort(array, mid+1,last);
		merge(array,first,mid,last);
	}
}

template<typename T>
void Print(T* r,int n)
{
	for (int i=0;i<n;i++)
	{
		cout << r[i] << endl;
	}
}

/* test
int main()
{
	cout << "Welcome..." << endl;
	double r[] = {1.5,3.2,5,6,9.2,7,2,4,8};
	//BubbleSort(r,9);
	QuickSort(r,0,8);
	//insert_sort(r,9);
	//shell_sort(r,9);
	//SelectSort(r,9);
	//HeapSort(r,9);
//	merge_sort(r,0,8);
	Print(r,9);

	return 0;
}
*/