排序问题

来源：互联网发布：制作简谱软件编辑：程序博客网时间：2024/06/03 09:26

题目描述 Description

给出n和n个整数，希望你从小到大给他们排序

输入描述 Input Description
第一行一个正整数n

第二行n个用空格隔开的整数
输出描述 Output Description

输出仅一行，从小到大输出n个用空格隔开的整数

样例输入 Sample Input
3

3 1 2

样例输出 Sample Output
1 2 3
数据范围及提示 Data Size & Hint

1<=n<=100000

（自己写的冒泡，和优化的快排死活都超时，直接用c++标准库里面的sort（）就通过了 OTL）

直接用标准库的代码：

#include <iostream>#include <algorithm>using namespace std;int main(){    int n;    cin >> n;    int * ar = new int[n];    for (int i = 0; i < n; i++)        cin >> ar[i];    sort(ar, ar+n);    for (int i = 0; i < n; i++)        cout << ar[i] << " ";    return 0;}

手写的快速排序和直接插入排序（超时）：

#include <iostream>using namespace std;const int MAX_LENGTH_INSERT_SORT = 7; // 数组小于等于7等用直接插入排序，大于7用快速排序void QuickSort(int ar[], int n);void QSort(int ar[], int low, int high); int Partition(int ar[], int low, int high);void Swap(int & a, int & b);void InsertSort(int ar[], int n); //插入排序int main(){    int n;    cin >> n;    int * ar = new int[n + 1];    for (int i = 1; i <= n; i++)        cin >> ar[i];    QuickSort(ar, n);    for (int i = 1; i <= n; i++)        cout << ar[i] << " ";    return 0;}void QuickSort(int ar[], int n){    QSort(ar, 1, n);}void QSort(int ar[], int low, int high){    int pivot;    if ((high - low) > MAX_LENGTH_INSERT_SORT)        {        while (low < high)        {            pivot = Partition(ar, low, high);   // 计算枢轴值            QSort(ar, low, pivot - 1);   //对低子表进行递归排序            low = pivot + 1;<span style="white-space:pre"></span>//末尾递归        }    }    else        InsertSort(ar, high);}int Partition(int ar[], int low, int high){    int pivotkey;    int m = low + ( high - low) / 2;      if (ar[low] > ar[high])        Swap(ar[low], ar[high]);    if (ar[m] > ar[high])        Swap(ar[m], ar[high]);    if (ar[m] > ar[low])        Swap(ar[m], ar[low]);          // 三数取中法    pivotkey = ar[low];    ar[0] = pivotkey;    while (low < high)    {        while (low < high && ar[high] >= pivotkey)            high--;        ar[low] = ar[high];        while(low < high && ar[low] <= pivotkey)            low++;        ar[high] = ar[low];    }    ar[low] = ar[0];    return low;}void InsertSort(int ar[], int n){    int j;    for (int i = 2; i <= n; i++)    {        if (ar[i] < ar[i-1])        {            ar[0] = ar[i];            for (j = i - 1; ar[j] > ar[0]; j--)                ar[j+1] = ar[j];            ar[j+1] = ar[0];        }    }}void Swap(int & a, int & b){    int temp;    temp = a;    a = b;    b = temp;}

优化的冒泡排序（超时）：

#include <iostream>using namespace std;int main(){    int n;    cin >> n;    int * ar = new int[n];    for (int i = 0; i < n; i++)        cin >> ar[i];    bool flag = true;    int temp;    for (int i = 0; i < n && flag; i++)    {        flag = false;        for (int j = n - 2; j >= i; j--)        {            if (ar[j] > ar[j+1])            {                temp = ar[j];                ar[j] = ar[j+1];                ar[j+1] = temp;                flag = true;            }        }    }    for (int i = 0; i < n; i++)        cout << ar[i] << " ";    return 0;}

ps：如有错误，欢迎指出

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