1.快速排序
#include<iostream>
#include<vector>
using namespace std;
class quicksort
{
public:
quicksort(vector<int>&num):nums(num){}
void sort(int low,int high);
void sort_();
void print();
private:
vector<int>nums;
};
void quicksort::sort(int low,int high)
{
if (low < high)
{
int tmp = nums[low];
int i = low, j = high;
while (i < j)
{
while (j>i&&nums[j] >= tmp)
j--;
nums[i] = nums[j];
while (j>i&&nums[i] < tmp)
i++;
nums[j] = nums[i];
}
nums[i] = tmp;
sort(low, i - 1);
sort(i + 1, high);
}
}
void quicksort::sort_()
{
int len = nums.size();
int low = 0, high = len - 1;
sort(low, high);
}
void quicksort::print()
{
for (auto i : nums)
cout << i << ' ';
}
2.归并排序
#include<iostream>
#include<vector>
using namespace std;
class mergesort
{
public:
mergesort(vector<int>&num):nums(num){}
void merge(int low, int high);
void sort(int low,int mid, int high);
void merge_();
void print();
private:
vector<int>nums;
vector<int>help;
};
void mergesort::merge(int low, int high)
{
if (low == high)
return;
int mid = (high-low)/2 + low;
merge(low, mid);
merge(mid + 1, high);
sort(low, mid,high);
}
void mergesort::sort(int low,int mid,int high)
{
int k = low;
int i = low, j = mid + 1;
while (i <= mid && j <= high)
{
if (nums[i] > nums[j])
help[k++] = nums[j++];
else
help[k++] = nums[i++];
}
while (i <= mid)
help[k++] = nums[i++];
while (j <= high)
help[k++] = nums[j++];
for (int p = low; p <= high; p++)
nums[p] = help[p];
}
void mergesort::merge_()
{
int len = nums.size();
help.resize(len);
merge(0, len - 1);
}
void mergesort::print()
{
for (auto i : nums)
cout << i << ' ';
}
3.堆排序
#include<vector>
#include<iostream>
#include<algorithm>
using namespace std;
class heapsort
{
public:
heapsort(vector<int>&num):nums(num){}
void makeheap();
void sort();
void adjustheap(int i,int len);
void printheap();
private:
vector<int>nums;
};
void heapsort::makeheap()
{
int len = nums.size();
for (int i = len / 2-1; i >= 0; i--)
{
adjustheap(i, len);
}
}
void heapsort::adjustheap(int i, int len)
{
int tmp = nums[i];
int j = 2 * i + 1;
while (j < len)
{
if (j + 1 < len&&nums[j] < nums[j + 1])
{
j++;
}
if (tmp > nums[j])
break;
nums[i] = nums[j];
i = j;
j = i * 2 + 1;
}
nums[i] = tmp;
}
void heapsort::sort()
{
for (int i = nums.size() - 1; i >= 0; i--)
{
swap(nums[i], nums[0]);
adjustheap(0, i);
}
}
void heapsort::printheap()
{
for (auto i:nums)
cout << i << ' ';
}
三个排序方法都是直接相比较的,因为平均时间复杂度都为nlogn