【整理】常见的排序算法

常见的排序算法

#include<iostream>
using namespace std;

void quick(int a[],int left, int right)
{
    if (left == right)
        return;
    int index = (right + left + 1) / 2;
    int temp;
    temp = a[index];
    a[index] = a[right];
    a[right] = temp;
    int p = 0;
    int prev = -1;
    while (p != right)
    {
        if (a[p] >= a[right])
        {
            if ((p - prev) != 1)
            {
                prev++;
                temp = a[p];
                a[p] = a[prev];
                a[prev] = temp;
            }
            else
                prev++;
        }
        p++;
    }
    prev++;
    temp = a[p];
    a[p] = a[prev];
    a[prev] = temp;
    if(prev!=left)
        quick(a, left, prev-1);
    if(prev!=right)
        quick(a, prev+1, right);
}

int main()
{
    int n,temp;
    cout << "请输入数组个数：" << endl;
    cin >> n;
    int *a = new int [n];
    for (int i = 0; i < n; i++)
    {
        cin >> temp;
        a[i] = temp;
    }
    
    //冒泡排序-从小到大
    for(int i=0;i<n-1;i++)
        for(int j=0;j<n-1-i;j++)
            if (a[j] > a[j + 1])
            {
                temp = a[j];
                a[j] = a[j + 1];
                a[j + 1] = temp;
            }
    for (int i = 0; i < n; i++)
        cout << a[i];
    cout << endl;

    //选择排序-从大到小
    int i,j,max;
    for (i = 0; i < n - 1; i++)
    {
        max = i;
        for (j = i; j < n; j++)
            if (a[j] > a[max])
                max = j;
        if (max != i)
        {
            temp = a[i];
            a[i] = a[max];
            a[max] = temp;
        }
    }
    for (int i = 0; i < n; i++)
        cout << a[i];
    cout << endl;

    //插入排序-从小到大
    for (i = 1; i < n; i++)
    {
        temp = a[i];
        j = i - 1;
        while (j >= 0 && a[j] > temp)
        {
            a[j + 1] = a[j];
            j--;
        }
        a[j + 1] = temp;
    }
    for (int i = 0; i < n; i++)
        cout << a[i];
    cout << endl;
    
    //快速排序-从大到小
    quick(a,0, n - 1);
    for (int i = 0; i < n; i++)
        cout << a[i];
    cout << endl;

    delete[] a;
    system("pause");
    return 0;

}