算法-QuickSort

 #include <stdlib.h>
 #include <iostream>
 #include <vector>

 using namespace std;

 template <class T>
 void print_array(const vector<T> &array)
 {
     for ( unsigned int i = ; i < array.size() + ; ++i )
     {
         cout<<array[i-]<<" ";
         if ( array[i - ] <  )
             cout<<" ";
         if ( i %  ==  )
             cout<<endl;
     }
 }

 template <class T>
 void shuffling(vector<T> &array)
 {
     int n = array.size();
     for ( int i = ; i < n; ++ i )
     {
         int r = i ==  ?  : rand() % i;
         T temp = array[i];
         array[i] = array[r];
         array[r] = temp;
     }

     return;
 }

 template <class T>
 unsigned int partition(vector<T> &array, unsigned int lo, int unsigned hi)
 {
     if ( lo == hi ) return lo;

     unsigned int i = lo;
     unsigned int j = hi;
     T partition_val = array[lo];

     while ( i < j )
     {
         while ( array[i] <= partition_val )
         {
             if ( i < hi ) ++i;
             else break;
         }

         while ( array[j] > partition_val )
         {
             if ( j > lo ) --j;
             else break;
         }

         if ( i < j )
         {
             T temp = array[i];
             array[i] = array[j];
             array[j] = temp;
         }

     }

     array[lo] = array[j];
     array[j] = partition_val;

     return j;
 }

 template <class T>
 void quick_sort(vector<T> &array, unsigned int  lo, unsigned int  hi)
 {
     if ( lo >= hi ) return;
     int partition_pos = partition(array, lo, hi);
     quick_sort(array, lo, partition_pos);
     quick_sort(array, partition_pos + , hi);

     return;
 }

 int main()
 {
     vector<int> array;
     for ( int i = ; i < ; ++i )
         array.push_back(i);

     cout<<"shuffling the array..."<<endl;
     shuffling(array);

     cout<<"the shuffled array: "<<endl;
     print_array(array);

     cout<<"quick sort the array: "<<endl;
     quick_sort(array, , array.size() - );

     cout<<"array after quick sorted: "<<endl;
     print_array(array);

     return ;
 }

输出结果：