void swap(int &a, int &b)
{
	int tmp = a;
	a = b;
	b = tmp;
}

//不使用中間變數的swap函式 

void swap_novar(int &a, int &b)
{
	if (a != b)
	{
		a ^= b;
		b ^= a;
		a ^= b;
	}
}

//快排演算法實現1

int Median3(int *a, int left, int right)
{
	int center = (left + right)/2;
	if(a[left] > a[center])
		swap(a[left], a[center]);
	if(a[left] > a[right])
		swap(a[left], a[right]);
	if(a[center] > a[right])
		swap(a[center], a[right]);
		
	swap(a[center], a[right-1]);
	return a[right-1];
}

void Qsort1(int *a, int left, int right)
{
	if(left >= right)
		return;

	int pivot = Median3(a, left, right);
	int i = left, j = right-1;
			
	while(1)
	{
		while(a[++i] < pivot);
		while(a[--j] > pivot);
		
		if(i < j)
			swap(a[i], a[j]);
		else
			break;
	}
	swap(a[i], a[right-1]);


	Qsort1(a, left, i-1);
	Qsort1(a, i+1, right);
}
 

//快排演算法實現2

void Qsort2(int *a, int left, int right)
{
	if(left < right)
	{
		int pivot = a[left];
		
		int i = left, j = right;
	
		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;
		
		Qsort2(a, left, i-1);
		Qsort2(a, i+1, right);
	}
}
 

//堆排序 

//堆向上調整，堆插入新元素時呼叫 
//新插入元素在堆末尾，也就是下標為n-1處 
//向上調整操作與堆排序無關
void MaxHeapFixUp(int a[], int n)
{
	
	int i = n - 1;
	int tmp = a[i];
	int father = (i - 1)/2;
	
	while(father >= 0 && i != 0)
	{
		if(a[father] > tmp)
			break;
		
		a[i] = a[father];
		
		i = father;
		father = (i - 1) / 2;
	}
	a[i] = tmp;
}
 

//最大堆向下調整，刪除堆頂元素時呼叫（堆排序時使用） 
void MaxHeapFixDown(int a[], int i, int n)
{
	int tmp = a[i];
	int lchild = 2*i + 1;
	
	while(lchild < n)
	{
		if( (lchild+1) < n && a[lchild] < a[lchild + 1])
			lchild++;
			
		if(a[lchild] < tmp)
			break;	
			
		a[i] = a[lchild];


		i = lchild;
		lchild = 2*i + 1;
	}
	a[i] = tmp;
}

//建最大堆

void MakeMaxHeap(int a[], int n)  
{  
	int i;
    for (i = n/2 - 1; i >= 0; i--)
        MaxHeapFixDown(a, i, n);
}  

//堆排序

void HeapSort(int a[], int n)
{
	MakeMaxHeap(a, n);
	
	int i = n-1;
	for(i = n-1; i > 0; --i)
	{
		swap(a[0], a[i]);
		MaxHeapFixDown(a, 0, i);
	}
}

//氣泡排序

void BubbleSort(int a[], int n)
{
	int i, j;
	
	for(i = 0; i < n; i++)
	{
		for(j = 0; j < n-i; j++)
		{
			if(a[j] > a[j+1])
				swap(a[j], a[j + 1]);
		}
	}
}

//新增標記flag，當序列已經全部有序後提前結束
void BubbleSort2(int a[], int n)
{
	int flag = 1;	
	while(flag)
	{
		flag = 0;
		for(int j = 0; j < n; j++)
		{
			if(a[j] > a[j+1])
			{
				swap(a[j], a[j + 1]);
				flag = 1;
			}
		}
		n--;
	}
}

//直接插入排序(Insertion Sort)：
//每次將一個待排序的記錄，按其關鍵字大小插入到前面已經排好序的子序列中的適當位置，直到全部記錄插入完成為止。

void InsertSort(int a[], int n)
{
	int i = 0;
	for(i = 1; i < n; i++)
	{
		int tmp = a[i];
		int j = i - 1;
		while(j >= 0 && a[j] > tmp)
		{
			a[j+1] = a[j];
			j--;
		}
		a[j+1] = tmp;
	}
}

//希爾排序：先取一個小於n的整數d1作為第一個增量，把檔案的全部記錄分組。所有距離為d1的倍數的記錄放在同一個組中。先在各組內進行直接插入排序；然後，取第二個增量d2<d1重複上述的分組和排序，直至所取的增量dt=1(dt<dt-l<…<d2<d1)，即所有記錄放在同一組中進行直接插入排序為止。 

void ShellSort(int a[], int n)
{
	int gap, i, j;
	for(gap = n/2; gap > 0; gap /= 2)
	{
		for(i = 0; i < gap; i++)
		{
			for(j = i + gap; j < n; j += gap)
			{
				int tmp = a[j];
				int k = j - gap;
				while(k >= 0 && a[k] > tmp)
				{
					a[k + gap] = a[k];
					k -= gap;
				}
				a[k + gap] = tmp;
			}
		}
	}
}

//直接選擇排序

void SelectSort(int a[], int n)
{
	int i, j;
	for(i = 0; i < n; ++i)
	{
		int min = a[i], k = i;
		for(j = i + 1; j < n; j++)
		{
			if(a[j] < min)
			{
				min = a[j];
				k = j;
			}
		}
		swap(a[i], a[k]);
	}
} 

//歸併排序

void merge(int a[], int tmparray[], int lpos, int rpos, int rightend)
{
	int leftend = rpos -  1;
	int tmppos = lpos;
	int num = rightend - lpos + 1;
	int i;
	while(lpos <= leftend && rpos <= rightend)
	{
		if(a[lpos] < a[rpos])
			tmparray[tmppos++] = a[lpos++];
		else
			tmparray[tmppos++] = a[rpos++];
	}	
	while(lpos <= leftend)
		tmparray[tmppos++] = a[lpos++];
	while(rpos <= rightend)
		tmparray[tmppos++] = a[rpos++];			

	for(i = 0; i < num; ++i, rightend--)
	{
		a[rightend] = tmparray[rightend];
	}
}

void Msort(int a[], int tmparray[], int left, int right)
{
	int mid;
	if(left < right)
	{
		mid = (left + right)/2;
		Msort(a, tmparray, left, mid);
		Msort(a, tmparray, mid + 1, right);
		merge(a, tmparray, left, mid + 1, right);
	}
}

void MergeSort(int a[], int n)
{
	int *tmparray = (int *)malloc(sizeof(int) * n);
	if(tmparray != NULL)
	{
		Msort(a, tmparray, 0, n-1);
		free(tmparray);
	}
}

二分查詢原始碼：

int binary_search(int array[], int n, int value)
{
	int left = 0;
	int right = n-1;
	while(left <= right)
	{
		int mid = left + ((<span style="color:#ff0000;">unsigned int</span>(right - left))>>1); //凡是右移操作時，一定要考慮有符號數符號擴充套件的問題
		if(array[mid] > value)
		{
			right = mid - 1;
		}
		else if(array[mid] < value)
		{
			left = mid + 1;
		}
		else
			return mid;
	}
	return -1;
}