归并排序和快速排序的算法实现

直接上代码
归并排序：

//将有二个有序数列a[first...mid]和a[mid...last]合并。
void mergearray(int a[], int first, int mid, int last, int temp[])
{
    int i = first, j = mid + 1;
    int m = mid,   n = last;
    int k = 0;

    while (i <= m && j <= n)
    {
        if (a[i] <= a[j])
            temp[k++] = a[i++];
        else
            temp[k++] = a[j++];
    }

    while (i <= m)
        temp[k++] = a[i++];

    while (j <= n)
        temp[k++] = a[j++];

    for (i = 0; i < k; i++)
        a[first + i] = temp[i];
}
void mergesort(int a[], int first, int last, int temp[])
{
    if (first < last)
    {
        int mid = (first + last) / 2;
        mergesort(a, first, mid, temp);    //左边有序
        mergesort(a, mid + 1, last, temp); //右边有序
        mergearray(a, first, mid, last, temp); //再将二个有序数列合并
    }
}

bool MergeSort(int a[], int n)
{
    int *p = new int[n];
    if (p == NULL)
        return false;
    mergesort(a, 0, n - 1, p);
    delete[] p;
    return true;
}

快速排序：

#include<iostream>
using namespace std;
void quickSort(int a[],int,int);
int main()
{
    int array[]={34,65,12,43,67,5,78,10,3,70},k;
    int len=sizeof(array)/sizeof(int);
    cout<<"The orginal arrayare:"<<endl;
    for(k=0;k<len;k++)
        cout<<array[k]<<",";
    cout<<endl;
    quickSort(array,0,len-1);
    cout<<"The sorted arrayare:"<<endl;
    for(k=0;k<len;k++)
        cout<<array[k]<<",";
    cout<<endl;
    system("pause");
    return 0;
}

void quickSort(int s[], int l, int r)
{
    if (l< r)
    {      
        int i = l, j = r, x = s[l];
        while (i < j)
        {
            while(i < j && s[j]>= x) // 从右向左找第一个小于x的数
                j--; 
            if(i < j)
                s[i++] = s[j];
            while(i < j && s[i]< x) // 从左向右找第一个大于等于x的数
                i++; 
            if(i < j)
                s[j--] = s[i];
        }
        s[i] = x;
        quickSort(s, l, i - 1); // 递归调用
        quickSort(s, i + 1, r);
    }
}