原地堆排序

 

原地堆排序算法：

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);
    }
}

 

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;
    }
}

测试代码：

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;
}