算法-MergeSort

 #include <iostream>
 #include <vector>
 #include <iterator>

 using namespace std;

 int COMPARE_COUNT = ;

 void merge_sort(vector<int> &array, vector<int> &aux, int lo, int hi)
 {
 if ( lo >= hi )
 return;

 int mid = ( hi + lo ) / ;
 merge_sort(array, aux, lo, mid);
 merge_sort(array, aux, mid + , hi);

 //vector<int> aux;
 for ( int i = lo; i < hi +; ++i )
 aux[i] = array[i];

 int i = lo;
 int j = mid + ;
 int k = lo;

 while ( k < hi +  )
 {
 if ( i > mid ) array[k++] = aux[j++];
 else if ( j > hi ) array[k++] = aux[i++];
 else if ( aux[i] <= aux[j] )
 {
 array[k++] = aux[i++];
 COMPARE_COUNT++;
 }
 else{
 array[k++] = aux[j++];
 COMPARE_COUNT++;
 }
 }

 return;
 }

 void Print(const vector<int> &array)
 {
 vector<int>::const_iterator _begin = array.begin();
 while ( _begin != array.end() )
 cout<<*_begin++<<" ";

 cout<<endl;
 }

 int main()
 {
 cout<<"Please input the size of the array: ";
 int size;
 cin>>size;

 vector<int> array;
 for ( int i = ; i < size; ++i )
 array.push_back( rand() % size + );

 cout<<"The shuffling array is:"<<endl;
 Print(array);

 vector<int> aux;
 aux.resize(array.size());
 //aux = array;
 merge_sort(array, aux, , size - );

 cout<<"The sorted array is:"<<endl;
 Print(array);

 //cout<<"Comparing count is: "<<COMPARE_COUNT<<endl;

 return ;
 }

输出结果：