求给十万个数排序的最好排序。

[hhjlgq]

如题，呵呵。一定要最快，如果谁最好，就分全给谁。

[djjlove_2008]

#include <iostream>
#include <ctime>
#include <cstdlib>

using namespace std;

const int M = 100000;
int Partition(int a[], int p, int r)
{
   int i = p; 
   int j = r + 1;
   int x = a[p];
   while(true)
   {
      while(a[++i] < x);
      while(a[--j] > x);
      if(i >= j)
         break;
      swap(a[i], a[j]);
   }
   a[p] = a[j];
   a[j] = x;
   
   return j;
}

int Random(int p, int r)
{
    int q = p + rand() % (r - p);
    return q;
}

int RandomizedPartition(int a[], int p, int r)
{
   int i = Random(p, r);
   swap(a[i], a[p]);
   return Partition(a, p, r);
}

void RandomizedQuickSort(int a[], int p, int r)
{
   if(p < r)
   {
      int q = RandomizedPartition(a, p, r);
      RandomizedQuickSort(a, p, q - 1);
      RandomizedQuickSort(a, q + 1, r);
   }
}

void PrintArray(int a[], int len)
{
   for(int i = 0; i < len; ++i)
     cout << a[i] << ' ';
   cout << endl;
}

int main()
{
    srand(unsigned(time(NULL)));
    int a[M] = {0};
    for(int i = 0; i < M; ++i)
       a[i++] = rand() % M;
       
    cout << "The original array is: ";
    PrintArray(a, M);
    
    clock_t start = clock();
    RandomizedQuickSort(a, 0, M);
        
    cout << "The sorted array is: ";
    PrintArray(a, M);
    cout << "The time is: " << (clock() - start) / CLK_TCK << endl;
    
    system("pause");
    return 0;
}

 

只花了４１秒。

[hhjlgq]

thanks very much.