快速排序算法分析--C++版

#include<stdlib.h>
#include<exception>
#include<stdexcept>
using namespace std;

// Random Partition
int RandomInRange(int min,int max)
{
    int random=rand()%(max-min+1)+min;
    return random;
}

// 两个数交换
void Swap(int* num1,int* num2)
{
    int temp=*num1;
    *num1=*num2;
    *num2=temp;
}

int Partition(int data[],int length,int start,int end)
{
    logic_error ex("Invalid Parameters");
    if(data==nullptr || length<=0 || start<0 || end>=length)
        throw exception(ex);

    int index=RandomInRange(start,end);
    Swap(&data[end],&data[index]);
   
    int small=start-1;
    for(index=start;index<end;++index)
    {
        if(data[index]<data[end])
	{
	    ++small;
	    if(small!=index)
	        Swap(&data[index],&data[small]);
	}
    }
    ++small;
    Swap(&data[small],&data[end]);
    return small;
}