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实现文件：
/*****************************************************************************
* sort.h
*
* Some sort algorithms.
*
* This file includes several usually used sorting algorithm, such as: bubble
* sorting, selection sorting, insertion sorting, quick sorting, merging
* sorting, and heap sorting.
*
* Zhang Ming, 2010-07
*****************************************************************************/
#ifndef SORT_H
#define SORT_H
#include <vector>
using namespace std;
namespace itlab
{
/**
* Bubble sort algorithm.
* "a" ----> array of Comparable items.
* "left" ----> the left-most index of the subarray.
* "right" ----> the right-most index of the subarray.
*/
template <typename Type>
void bubbleSort( vector<Type> &a, int left, int right )
{
bool cond;
for( int i=left; i<right; ++i )
{
cond = false;
for( int j=right; j>i; --j )
if( a[j] < a[j-1] )
{
swap( a[j], a[j-1] );
cond = true;
}
if( !cond )
return;
}
}
/**
* Selection sort algorithm.
* "a" ----> array of Comparable items.
* "left" ----> the left-most index of the subarray.
* "right" ----> the right-most index of the subarray.
*/
template <typename Type>
void selectSort( vector<Type> &a, int left, int right )
{
Type minPos;
for( int i=left; i<right; ++i )
{
minPos = i;
for( int j=i+1; j<=right; ++j )
if( a[j] < a[minPos] )
minPos = j;
if( i != minPos )
swap( a[i], a[minPos] );
}
}
/**
* Insertion sort algorithm.
* "a" ----> array of Comparable items.
* "left" ----> the left-most index of the subarray.
* "right" ----> the right-most index of the subarray.
*/
template <typename Type>
void insertSort( vector<Type> &a, int left, int right )
{
for( int p=left+1; p<=right; p++ )
{
Type tmp = a[p];
int j;
for( j=p; j>left && tmp<a[j-1]; --j )
a[j] = a[j-1];
a[j] = tmp;
}
}
/**
* Return median of left, center, and right.
* Order these and hide the pivot.
*/
template <typename Type>
const Type& median3( vector<Type> &a, int left, int right )
{
int center = (left+right) / 2;
if( a[center] < a[left] )
swap( a[left], a[center] );
if( a[right] < a[left] )
swap( a[left], a[right] );
if( a[right] < a[center] )
swap( a[center], a[right] );
swap( a[center], a[right-1] );
return a[right-1];
}
/**
* Internal quicksort method that makes recursive calls.
* Uses median-of-three partitioning and a cutoff of 20.
* "a" ----> array of Comparable items.
* "left" ----> the left-most index of the subarray.
* "right" ----> the right-most index of the subarray.
*/
template <typename Type>
void quickSort( vector<Type> &a, int left, int right )
{
if( left+20 <= right )
{
Type pivot = median3( a, left, right );
// begin partitioning
int i = left, j = right-1;
for( ; ; )
{
while( a[++i] < pivot ) { }
while( pivot < a[--j] ) { }
if( i < j )
swap( a[i], a[j] );
else
break;
}
// Restore pivot
swap( a[i], a[right-1] );
// Sort small elements
quickSort( a, left, i-1 );
// Sort large elements
quickSort( a, i+1, right );
}
else
insertSort( a, left, right );
}
/**
* Merg two subsequence to a bigger one.
* The first subsequence is a[left1] ... a[right1], and
* The second subsqeuence is a[left2] ... a[right2].
*/
template <typename Type>
void merg( vector<Type> &a, int left1, int right1, int left2, int right2 )
{
int k = 0,
i = left1,
j = left2,
n1 = right1-left1+1,
n2 = right2-left2+1;
Type *tmp = new Type[n1+n2];
while( i <= right1 && j <= right2 )
if( a[i] < a[j] )
tmp[k++] = a[i++];
else
tmp[k++] = a[j++];
while( i <= right1 )
tmp[k++] = a[i++];
while( j <= right2 )
tmp[k++] = a[j++];
for( int i=0; i<n1; ++i )
a[left1++] = tmp[i];
for( int i=0; i<n2; ++i )
a[left2++] = tmp[n1+i];
delete []tmp;
}
/**
* Merg sort algorithm (nonrecursion).
* "a" ----> array of Comparable items.
* "left" ----> the left-most index of the subarray.
* "right" ----> the right-most index of the subarray.
*/
template <typename Type>
void mergSort( vector<Type> &a, int left, int right )
{
int left1, right1, left2, right2,
n = right - left + 1,
size = 1;
while( size < n )
{
left1 = left;
while( left1+size < n )
{
left2 = left1+size;
right1 = left2-1;
if( left2+size > n )
right2 = right;
else
right2 = left2+size-1;
merg( a, left1, right1, left2, right2 );
left1 = right2+1;
}
size *= 2;
}
}
/**
* Heap sort algorthm.
* "a" ----> array of Comparable items.
* "left" ----> the left-most index of the subarray.
* "right" ----> the right-most index of the subarray.
*/
template <typename Type>
void heapSort( vector<Type> &a, int left, int right )
{
int n = right-left+1;
vector<Type> tmp( n );
for( int i=0; i<n; ++i )
tmp[i] = a[left+i];
for( int i=n/2; i>=0; --i )
filterDown( tmp, i, n );
for( int j=n-1; j>0; --j )
{
swap( tmp[0], tmp[j] );
filterDown( tmp, 0, j );
}
for( int i=0; i<n; ++i )
a[left+i] = tmp[i];
}
/**
* Percolate down the heap.
* "i" ----> the position from which to percolate down.
* "n" ----> the logical size of the binary heap.
*/
template <typename Type>
void filterDown( vector<Type> &a, int i, int n )
{
int child;
Type tmp;
for( tmp=a[i]; 2*i+1<n; i=child )
{
child = 2*i+1;
if( child!=n-1 && a[child]<a[child+1] )
child++;
if( tmp < a[child] )
a[i] = a[child];
else
break;
}
a[i] = tmp;
}
}
// namespace itlab
#endif
// SORT_H
测试文件：
/*****************************************************************************
* sort_test.cpp
*
* Sorting algorithm testing.
*
* Zhang Ming, 2009-10
*****************************************************************************/
#include <iostream>
#include <random.h>
#include <sort.h>
using namespace std;
using namespace itlab;
const int SIZE = 10;
template <typename Type>
void printVector( const vector<Type> &a )
{
vector<int>::const_iterator itr = a.begin();
while( itr != a.end() )
cout << *itr++ << "\t";
cout << endl;
}
int main()
{
vector<int> a( SIZE );
cout << "Unsorted Numbers : " << endl;
Random r(127);
for( unsigned i=0; i<a.size(); ++i )
a[i] = r.random( 1, 10*SIZE );
printVector( a );
cout << "Bubble Sorted Numbers : " << endl;
bubbleSort( a, 0, a.size()-1 );
printVector( a );
cout << endl;
cout << "Unsorted Numbers : " << endl;
for( unsigned i=0; i<a.size(); ++i )
a[i] = r.random( 1, 10*SIZE );
printVector( a );
cout << "Select Sorted Numbers : " << endl;
selectSort( a, 0, a.size()-1 );
printVector( a );
cout << endl;
cout << "Unsorted Numbers : " << endl;
for( unsigned i=0; i<a.size(); ++i )
a[i] = r.random( 1, 10*SIZE );
printVector( a );
cout << "Insert Sorted Numbers : " << endl;
insertSort( a, 0, a.size()-1 );
printVector( a );
cout << endl;
cout << "Unsorted Numbers : " << endl;
for( unsigned i=0; i<a.size(); ++i )
a[i] = r.random( 1, 10*SIZE );
printVector( a );
cout << "Quick Sorted Numbers : " << endl;
quickSort( a, 0, a.size()-1 );
printVector( a );
cout << endl;
cout << "Unsorted Numbers : " << endl;
for( unsigned i=0; i<a.size(); ++i )
a[i] = r.random( 1, 10*SIZE );
printVector( a );
cout << "Merg Sorted Numbers : " << endl;
mergSort( a, 0, a.size()-1 );
printVector( a );
cout << endl;
cout << "Unsorted Numbers : " << endl;
for( unsigned i=0; i<a.size(); ++i )
a[i] = r.random( 1, 10*SIZE );
printVector( a );
cout << "Heap Sorted Numbers : " << endl;
heapSort( a, 0, a.size()-1 );
printVector( a );
cout << endl;
return 0;
}
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