Heap-005-Heap-Sort

Heap.h

#ifndef INC_06_HEAP_SORT_HEAP_H
#define INC_06_HEAP_SORT_HEAP_H

#include <algorithm>
#include <cassert>

using namespace std;


template<typename Item>
class MaxHeap{

private:
    Item *data;
    int count;
    int capacity;

    void shiftUp(int k){
        while( k > 1 && data[k/2] < data[k] ){
            swap( data[k/2], data[k] );
            k /= 2;
        }
    }

    void shiftDown(int k){
        while( 2*k <= count ){
            int j = 2*k;
            if( j+1 <= count && data[j+1] > data[j] ) j ++;
            if( data[k] >= data[j] ) break;
            swap( data[k] , data[j] );
            k = j;
        }
    }

public:

    MaxHeap(int capacity){
        data = new Item[capacity+1];
        count = 0;
        this->capacity = capacity;
    }

    MaxHeap(Item arr[], int n){
        data = new Item[n+1];
        capacity = n;

        for( int i = 0 ; i < n ; i ++ )
            data[i+1] = arr[i];
        count = n;

        for( int i = count/2 ; i >= 1 ; i -- )
            shiftDown(i);
    }

    ~MaxHeap(){
        delete[] data;
    }

    int size(){
        return count;
    }

    bool isEmpty(){
        return count == 0;
    }

    void insert(Item item){
        assert( count + 1 <= capacity );
        data[count+1] = item;
        shiftUp(count+1);
        count ++;
    }

    Item extractMax(){
        assert( count > 0 );
        Item ret = data[1];
        swap( data[1] , data[count] );
        count --;
        shiftDown(1);
        return ret;
    }

    Item getMax(){
        assert( count > 0 );
        return data[1];
    }
};

#endif

HeapSort.h

#ifndef INC_06_HEAP_SORT_HEAPSORT_H
#define INC_06_HEAP_SORT_HEAPSORT_H

#include "Heap.h"

using namespace std;


template<typename T>
void heapSort2(T arr[], int n){

    MaxHeap<T> maxheap = MaxHeap<T>(arr,n);
    for( int i = n-1 ; i >= 0 ; i-- )
        arr[i] = maxheap.extractMax();

}


template<typename T>
void heapSort1(T arr[], int n){

    MaxHeap<T> maxheap = MaxHeap<T>(n);
    for( int i = 0 ; i < n ; i ++ )
        maxheap.insert(arr[i]);

    for( int i = n-1 ; i >= 0 ; i-- )
        arr[i] = maxheap.extractMax();

}
#endif

main.cpp

#include <iostream>
#include <algorithm>
#include "MergeSort.h"
#include "QuickSort.h"
#include "HeapSort.h"
#include "SortTestHelper.h"

using namespace std;


template<typename T>
void __shiftDown(T arr[], int n, int k){

    while( 2*k+1 < n ){
        int j = 2*k+1;
        if( j+1 < n && arr[j+1] > arr[j] )
            j += 1;

        if( arr[k] >= arr[j] )break;

        swap( arr[k] , arr[j] );
        k = j;
    }
}

template<typename T>
void __shiftDown2(T arr[], int n, int k){

    T e = arr[k];
    while( 2*k+1 < n ){
        int j = 2*k+1;
        if( j+1 < n && arr[j+1] > arr[j] )
            j += 1;

        if( e >= arr[j] ) break;


        arr[k] = arr[j];
        k = j;
    }

    arr[k] = e;
}

template<typename T>
void heapSort(T arr[], int n){

    for( int i = (n-1)/2 ; i >= 0 ; i -- )
        __shiftDown2(arr, n, i);

    for( int i = n-1; i > 0 ; i-- ){
        swap( arr[0] , arr[i] );
        __shiftDown2(arr, i, 0);
    }
}


int main() {

    int n = 1000000;

    // 测试1 一般性测试
    cout<<"Test for Random Array, size = "<<n<<", random range [0, "<<n<<"]"<<endl;
    int* arr1 = SortTestHelper::generateRandomArray(n,0,n);
    int* arr2 = SortTestHelper::copyIntArray(arr1, n);
    int* arr3 = SortTestHelper::copyIntArray(arr1, n);
    int* arr4 = SortTestHelper::copyIntArray(arr1, n);
    int* arr5 = SortTestHelper::copyIntArray(arr1, n);
    int* arr6 = SortTestHelper::copyIntArray(arr1, n);

    SortTestHelper::testSort("Merge Sort", mergeSort, arr1, n);
    SortTestHelper::testSort("Quick Sort", quickSort, arr2, n);
    SortTestHelper::testSort("Quick Sort 3 Ways", quickSort3Ways, arr3, n);
    SortTestHelper::testSort("Heap Sort 1", heapSort1, arr4, n);
    SortTestHelper::testSort("Heap Sort 2", heapSort2, arr5, n);
    SortTestHelper::testSort("Heap Sort 3", heapSort, arr6, n);

    delete[] arr1;
    delete[] arr2;
    delete[] arr3;
    delete[] arr4;
    delete[] arr5;
    delete[] arr6;

    cout<<endl;


    // 测试2 测试近乎有序的数组
    int swapTimes = 100;
    cout<<"Test for Random Nearly Ordered Array, size = "<<n<<", swap time = "<<swapTimes<<endl;
    arr1 = SortTestHelper::generateNearlyOrderedArray(n,swapTimes);
    arr2 = SortTestHelper::copyIntArray(arr1, n);
    arr3 = SortTestHelper::copyIntArray(arr1, n);
    arr4 = SortTestHelper::copyIntArray(arr1, n);
    arr5 = SortTestHelper::copyIntArray(arr1, n);
    arr6 = SortTestHelper::copyIntArray(arr1, n);

    SortTestHelper::testSort("Merge Sort", mergeSort, arr1, n);
    SortTestHelper::testSort("Quick Sort", quickSort, arr2, n);
    SortTestHelper::testSort("Quick Sort 3 Ways", quickSort3Ways, arr3, n);
    SortTestHelper::testSort("Heap Sort 1", heapSort1, arr4, n);
    SortTestHelper::testSort("Heap Sort 2", heapSort2, arr5, n);
    SortTestHelper::testSort("Heap Sort 3", heapSort, arr6, n);

    delete[] arr1;
    delete[] arr2;
    delete[] arr3;
    delete[] arr4;
    delete[] arr5;
    delete[] arr6;

    cout<<endl;


    // 测试3 测试存在包含大量相同元素的数组
    cout<<"Test for Random Array, size = "<<n<<", random range [0,10]"<<endl;
    arr1 = SortTestHelper::generateRandomArray(n,0,10);
    arr2 = SortTestHelper::copyIntArray(arr1, n);
    arr3 = SortTestHelper::copyIntArray(arr1, n);
    arr4 = SortTestHelper::copyIntArray(arr1, n);
    arr5 = SortTestHelper::copyIntArray(arr1, n);
    arr6 = SortTestHelper::copyIntArray(arr1, n);

    SortTestHelper::testSort("Merge Sort", mergeSort, arr1, n);
    SortTestHelper::testSort("Quick Sort", quickSort, arr2, n);
    SortTestHelper::testSort("Quick Sort 3 Ways", quickSort3Ways, arr3, n);
    SortTestHelper::testSort("Heap Sort 1", heapSort1, arr4, n);
    SortTestHelper::testSort("Heap Sort 2", heapSort2, arr5, n);
    SortTestHelper::testSort("Heap Sort 3", heapSort, arr6, n);

    delete[] arr1;
    delete[] arr2;
    delete[] arr3;
    delete[] arr4;
    delete[] arr5;
    delete[] arr6;


    return 0;
}