排序算法-冒泡、插入、归并、希尔、快速、选择--代码总结

冒泡排序代码：

#include <iostream>
#include <string>

using namespace std;
template<class ItemType>

void bubbleSort(ItemType theArray[], int n)
{
   bool sorted = false; // False when swaps occur
   int pass = 1;
   while (!sorted && (pass < n))
   {
      // At this point, theArray[n+1-pass..n-1] is sorted
      // and all of its entries are > the entries in theArray[0..n-pass]
      sorted = true; // Assume sorted
      for (int index = 0; index < n - pass; index++)
      {
         // At this point, all entries in theArray[0..index-1]
         // are <= theArray[index]
         int nextIndex = index + 1;
         if (theArray[index] > theArray[nextIndex])
         {
            // Exchange entries
            std::swap(theArray[index], theArray[nextIndex]);
            sorted = false; // Signal exchange
         } // end if
      }  // end for
      // Assertion: theArray[0..n-pass-1] < theArray[n-pass]
      
      pass++;
   }  // end while
}  // end bubbleSort

int main()
{
   string a[6] = {"Z", "X", "R", "K", "F", "B"};
   bubbleSort(a, 6);
   for (int i = 0; i < 6; i++)
      cout << a[i] << " ";
   cout << endl;   
}  // end main

插入排序代码：

#include <iostream>
#include <string>

using namespace std;
template<class ItemType>

void insertionSort(ItemType theArray[], int n)
{
   
   for (int unsorted = 1; unsorted < n; unsorted++)
   {
      ItemType nextItem = theArray[unsorted];
      int loc = unsorted;
      while ((loc > 0) && (theArray[loc - 1] > nextItem))
      {
         // Shift theArray[loc - 1] to the right
         theArray[loc] = theArray[loc - 1];
         loc--;
      }  // end while
      
      // At this point, theArray[loc] is where nextItem belongs
      theArray[loc] = nextItem; // Insert nextItem into sorted region
   }  // end for
}  // end insertionSort

int main()
{
   string a[6] = {"Z", "X", "R", "K", "F", "B"};
   insertionSort(a, 6);
   for (int i = 0; i < 6; i++)
      cout << a[i] << " ";
   cout << endl;
}  // end main

归并排序代码：

#include <iostream>
#include <string>

using namespace std;

const int MAX_SIZE = 50;

template<class ItemType>

void merge(ItemType theArray[], int first, int mid, int last)
{
   ItemType tempArray[MAX_SIZE];  // Temporary array
   
   int first1 = first;            // Beginning of first subarray
   int last1 = mid;               // End of first subarray
   int first2 = mid + 1;          // Beginning of second subarray
   int last2 = last;              // End of second subarray
   
   int index = first1;            // Next available location in tempArray
   while ((first1 <= last1) && (first2 <= last2))
   {
      // At this point, tempArray[first..index-1] is in order
      if (theArray[first1] <= theArray[first2])
      {
         tempArray[index] = theArray[first1];
         first1++;
      }
      else
      {
         tempArray[index] = theArray[first2];
         first2++;
      }  // end if
      index++;
   }  // end while
   
   // Finish off the first subarray, if necessary
   while (first1 <= last1)
   {
      // At this point, tempArray[first..index-1] is in order
      tempArray[index] = theArray[first1];
      first1++;
      index++;
   }  // end while
   
   // Finish off the second subarray, if necessary
   while (first2 <= last2)
   {
      // At this point, tempArray[first..index-1] is in order
      tempArray[index] = theArray[first2];
      first2++;
      index++;
   }  // end for
   
   // Copy the result back into the original array
   for (index = first; index <= last; index++)
      theArray[index] = tempArray[index];
}  // end merge


void mergeSort(ItemType theArray[], int first, int last)
{
   if (first < last)
   {
      // Sort each half
      int mid = first + (last - first) / 2; // Index of midpoint
      
      // Sort left half theArray[first..mid]
      mergeSort(theArray, first, mid);
      
      // Sort right half theArray[mid+1..last]
      mergeSort(theArray, mid + 1, last);
      
      // Merge the two halves
      merge(theArray, first, mid, last);
   }  // end if
}  // end mergeSort

int main()
{
   string a[6] = {"Z", "X", "R", "K", "F", "B"};
   mergeSort(a, 0, 5);
   for (int i = 0; i < 6; i++)
      cout << a[i] << " ";
   cout << endl;
   
}  // end main

 

希尔排序代码：

void shellSort(ItemType theArray[], int n)
{
   for (int h = n / 2; h > 0; h = h / 2)
   {
      for (int unsorted = h; unsorted < n; unsorted++)
      {
         ItemType nextItem = theArray[unsorted];
         int loc = unsorted;
         while ( (loc >= h) && (theArray[loc - h] > nextItem) )
         {
            theArray[loc] = theArray[loc - h];
            loc = loc - h;
         } // end while
         theArray[loc] = nextItem;
      }  // end for
   }  // end for
}  // end shellSort

快速排序代码：

int partition(int *arr,int low,int high)
{
    int pivot=arr[high];
    int i=low-1;
    int j;
    for(j=low;j<high;++j)
        if(arr[j]<pivot)
			swap(arr[++i],arr[j]);
   swap(arr[i+1],arr[high]);
    return i+1;
}

void quickSort(int theArray[], int first, int last)
{
       // Create the partition: S1 | Pivot | S2
	if(first < last)
	{
      int pivotIndex = partition(theArray, first, last);
      
      // Sort subarrays S1 and S2
      quickSort(theArray, first, pivotIndex - 1);
      quickSort(theArray, pivotIndex + 1, last);
 }  // end if
}

选择排序代码：

void selectionSort(ItemType theArray[], int n)
{
  
   for (int last = n - 1; last >= 1; last--)
   {
      int largest = findIndexofLargest(theArray, last+1);
      std::swap(theArray[largest], theArray[last]);
   }  // end for
}  // end selectionSort

int findIndexofLargest(const ItemType theArray[], int size)
{
   int indexSoFar = 0; // Index of largest entry found so far
   for (int currentIndex = 1; currentIndex < size; currentIndex++)
   {
      
      if (theArray[currentIndex] > theArray[indexSoFar])
         indexSoFar = currentIndex;
   }  // end for
   return indexSoFar; // Index of largest entry
}  // end findIndexofLargest