排序算法汇总

桶排序

#include <iostream>
using namespace std;

int main () {
int book[1001]; // 下标是0-1000
int temp; //用来临时存放读取的数
for (int i = 0; i <= 1001; i++)
    {
        book[i] = 0; //完成初始化
    }
int num; //设定有几个数进行比较
cin >> num; 
for (int i = 1; i <= num; i++)
    {
cin >> temp; 
        book[temp] ++ ;
    } //进行桶排序
for (int i = 1000; i >= 0; i--)
    {
for (int j = 1; j <= book[i]; j++)
        {
cout << i <<" ";
        }
    } //1000到0 每个桶看一遍，桶里有几个球就打印这个桶标号几次
    system("pause");
}

冒泡排序

#include <iostream>
using namespace std;

int main () {
int a[100];
int num;
cin >> num;
for (int i = 0; i < num; i++)
    {
cin >> a[i];
    }
/*以下为冒泡排序
 */
for (int i = 0; i < num; i++)
    {
for (int j = 0; j < num - i; j++)
        {
if (a[j] < a[j+ 1])
            {
int temp = a[j];
                a[j] = a[j + 1];
                a[j + 1] = temp;
            }
        }
    }
//循环输出
for (int i = 0; i < num; i++)
    {
cout << a[i] << " ";
    }
    system("pause");
}

改进：对学生信息进行排序，根据成绩高低排序，输出成绩与姓名

#include <iostream>
using namespace std;

struct student
{
char name[21];
int score;
};
int main () {
struct student a[100];
int n; cin >> n;
for (int i = 0; i < n; i++)
    {
cin >> a[i].name >> a[i].score;
    }

//排序，按照成绩高低
for (int i = 0; i < n; i++)
    {
for (int j = 0; j < n - i; j++)
        {
if (a[j].score < a[j + 1].score)
            {
struct student temp = a[j];
                a[j] = a[j + 1];
                a[j + 1] = temp;
            }
        }
    }
//输出成绩高低及 名字
cout << "成绩高低及分数为： " << endl;
for (int i = 0; i < n; i++)
    {
cout << a[i].name << ' ' << a[i].score << endl;
    }
    system("pause");
}

快速排序

#include <iostream>
using namespace std;

int a[100];//存放数据
int n; //表示有几个数

void quicksort (int left , int right) {
int temp = a[left];//就是存基数的
int i = left;
int j = right;
if (left > right)
    {
return; 
    } 
while (i != j)
    {
//顺序很重要，得先从右往左找
while (a[j] >= temp && i < j) j --;
while (a[i] <= temp && i < j ) i ++;
if (true)
                {
int t = a[i];
                    a[i] = a[j];
                    a[j] = t; 
                }
    }
//然后将基数归位，就是最左边的数
    a[left] = a[i]; //就是最左边的那个基准数跟在 中间它本该在的位子上那个数交换
    a[i] = temp; //temp一直存放着基准数，就是最左边的数
//然后进行递归
    quicksort(left, i -1);
    quicksort(i + 1, right);
return ;
}

int main () {
cout << "输入要排序的数的个数" << endl;
cin >> n;
cout << "输入每个数" << endl;
for (int i = 0; i < n; i++)
    {
cin >> a[i];
    }
    quicksort(0, n-1);
cout << "排完序后为： " << endl;
for (int i = 0; i < n; i++)
    {
cout << a[i] << " " ;
    }
    system("pause");
}