Quicksort-优快云博客

本文介绍了一个使用C++实现的快速排序算法。该算法通过递归地将数组分为较小和较大的两个子集，并对这两个子集进行排序来实现整个数组的排序。输入为一组整数，输出为升序排列的整数序列。

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Description

#include <iostream>
using namespace std;
#define maxlen 100000
int partition(int a[], int p, int r)
{
    int x = a[r];
    int i = p - 1, j;
    for (j = p; j < r; j++)
    {
        if (a[j] <= x)
        {
            i = i + 1;
            int temp1 = a[i];
            a[i] = a[j];
            a[j] = temp1;
        }
    }
    int temp2 = a[i + 1];
    a[i + 1] = a[r];
    a[r] = temp2;
    return i + 1;
}
 
void quicksort(int a[], int first, int last)
{
    if (first < last)
    {
        int q = partition(a, first, last);
        quicksort(a, first, q - 1);
        quicksort(a, q, last);
    }
}
 
int main()
{
    int n;
    while (cin >> n)
    {
        int a[maxlen];
        int i;
        for (i = 0; i < n; i++)
            cin >> a[i];
        quicksort(a, 0, n - 1);
        for (i = 0; i < n-1; i++)
            cout << a[i]<<" ";
        cout << a[i];
        cout << endl;
    }
    return 0;
}
/**************************************************************
    Problem: ****
    User: Avivadepp
    Language: C++
    Result: Accepted
    Time:4 ms
    Memory:1596 kb
****************************************************************/

快速排序

Input

For each of the input, the first line of the input will be the size of the array (size < 1,000,000), and the second line is the integers in the array, separated by commas.