快速排序

2015.11.30 面试创云传奇

#include <iostream>
#include <cstdlib>
#include <vector>

using namespace std;

#define random(x) (rand()%x)

void quick_sort(vector<int>& vec, int left, int right)
{
	if(left < right)
	{
		int pivot = vec[left];
		int low = left;
		int high = right;
		while(low < high)
		{
			while(low < high && vec[high] >= pivot)
				high--;
			vec[low] = vec[high];

			while(low < high && vec[low] <= pivot)
				low++;
			vec[high] = vec[low];
		}

		vec[low] = pivot;

		quick_sort(vec, left, low-1);
		quick_sort(vec, low+1, right);
	}
}

void print_num(vector<int>& vec)
{
	int len = vec.size();
	for(int i = 0; i < len; i++)
		cout << vec[i] << ' ';

	cout << endl;
}

int main()
{
	vector<int> vec;
	for(int i = 0; i < 10; i++)
	{
		int num = random(10);
		vec.push_back(num);
	}

	print_num(vec);
	int len = vec.size();
	quick_sort(vec, 0, len-1);
	print_num(vec);

	return 0;
}