快速排序平均时间复杂度是O(nlogn)，最坏时间复杂度是O(n^2)，空间复杂度也是O(nlogn)，是不稳定排序算法。

主要实现思想：通过分区，首先选取基节点，基节点满足左边数据小于基节点，右边数据大于基节点；当完成一趟分区后，取得中间值，对左边数据同样进行分区满足“基节点左小右大”性质，对右边同样进行分区满足“基节点左小右大”性质，一直递归，直到左边数据哨兵指针大于等于右边哨兵指针即为结束条件。

void Sorts::quick(vector<int>& nums, int left, int right)
{if (left >= right)return;int middle = partition(nums, left, right);quick(nums, left, middle - 1);quick(nums, middle + 1, right);
}

下面是实现选择排序算法代码

Sorts.h

#pragma once#include <iostream>
#include <vector>using namespace std;struct Sorts {    void quick(vector<int>& nums);void print(vector<int>& nums);private:void quick(vector<int>& nums, int left, int right);int partition(vector<int>& nums, int left, int right);
};

Sorts.cpp

#include "Sorts.h"void Sorts::quick(vector<int>& nums)
{quick(nums, 0, nums.size() - 1);
}void Sorts::quick(vector<int>& nums, int left, int right)
{if (left >= right)return;int middle = partition(nums, left, right);quick(nums, left, middle - 1);quick(nums, middle + 1, right);
}int Sorts::partition(vector<int>& nums, int left, int right)
{int i = rand() % (right - left + 1) + left; // 取随即基节点，排序效率最佳swap(nums[i], nums[left]);int pivot = nums[left]; // 取第一个基节点int lSentry = left + 1;int rSentry = right;while (lSentry < rSentry) // 遍历整个数组{while (lSentry < rSentry && nums[lSentry] < pivot) // 找到第一个大于基准值下标，加上校验判断优化性能++lSentry;while (lSentry < rSentry && nums[rSentry] > pivot) // 找到第一个小于基准值下标，加上校验判断优化性能--rSentry;if (lSentry < rSentry){swap(nums[lSentry], nums[rSentry]); //交换左右哨兵值++lSentry;--rSentry;}        }if (nums[rSentry] > pivot) // lSentry >= rSentry--rSentry;swap(nums[rSentry], nums[left]); // 中间集结点归属到左边部分return rSentry; // 返回右边哨兵作为中间值
}void Sorts::print(vector<int>& nums)
{for (const auto& it : nums)cout << it << ",";cout << endl;
}

main.cpp

 #include <vector>
#include "Sorts.h"using namespace std;int main()
{vector<int> nums = { 2,0,1,6,8,10,5,99,87,333,2,0,1 };Sorts sorts;sorts.print(nums);sorts.quick(nums);sorts.print(nums);return 1;
}