常用排序算法

1. 冒泡排序

#include <iostream>
#include <algorithm>
#include <stdlib.h>
using namespace std;

void bubble_sort(int a[], int n)
{
    for (int i = 1; i < n; i++)
    {
        bool flag = true;
        for (int j = 0; j < n - i; j++)
        {
            if (a[j] > a[j+1])
                swap(a[j], a[j+1]);
            flag = false;
        }
        if (flag == false)
            break;
    }
}

int main(void)
{
    int a[] ={5,4,9,5,2,7};
    bubble_sort(a, 6);
    for (int i = 0; i < 6; i++)
    {
        cout<<a[i]<<endl;
    }
    system("pause");
}

2. 选择排序

#include <iostream>
#include <algorithm>
#include <stdlib.h>
using namespace std;

void select_sort(int a[], int n)
{
    for (int i =0; i < n; i++)
    {
        int min_index = i;
        for(int j = i + 1; j < n; j++)
        {
            if (a[j] < a[min_index])
                min_index = j;
        }
        swap(a[i], a[min_index]);
    }
}

int main(void)
{
    int a[] ={5,4,9,5,2,7};
    select_sort(a, 6);
    for (int i = 0; i < 6; i++)
    {
        cout<<a[i]<<endl;
    }
    system("pause");
}

3. 快速排序

4. 归并排序