C++算法之堆排序的代码

将开发过程中比较常用的内容段做个珍藏，如下的内容段是关于C++算法之堆排序的内容。

void heap_sort(int array[], int length)  
{  
    if(NULL == array || 0 == length)  
        return ;  
  
    _heap_sort(array-1, length);  
}  

b）构建大堆和调整大堆

void _heap_sort(int array[], int length)  
{  
    int index = 0;  
    int median = 0;  
    construct_big_heap(array, length);  
  
    for(index = length; index > 1; index --)  
    {  
        median = array[1];  
        array[1] = array[index];  
        array[index] = median;  
  
        reconstruct_heap(array, 1, index-1);  
    }  
}  

c）构建大堆的细节操作部分

void set_sorted_value(int array[], int length)  
{  
    int index = length;  
    int median = 0;  
    if(length == 1) return;  
  
    while(index > 1){  
        if(array[index >> 1] >= array[index])  
            break;  
  
        median = array[index];  
        array[index] = array[index >> 1];  
        array[index >> 1] = median;  
        index >>= 1;  
    }  
}  
  
void construct_big_heap(int array[], int length)  
{  
    int index = 0 ;  
  
    for(index = 1; index <= length; index ++)  
    {  
        set_sorted_value(array, index);  
    }  
}  

d）大堆迭代调整

void reconstruct_heap(int array[], int index, int length)  
{  
    int swap = 0;  
    if(length < index << 1)  
        return;  
  
    if(length == index << 1){  
        adjust_leaf_position(array, index);  
        return;  
    }  
  
    if(-1 != (swap = adjust_normal_position(array, index))){  
        reconstruct_heap(array, swap, length);  
    }  
}  

e）对单分支节点和满分支节点分别处理

int adjust_normal_position(int array[], int index)  
{  
    int left = index << 1 ;  
    int right = left + 1;  
    int median = 0;  
    int swap = 0;  
  
    if(array[index] >= array[left]){  
        if(array[index] >= array[right]){  
            return -1;  
        }else{  
            swap = right;  
        }  
    }else{  
        if(array[index] >= array[right]){  
            swap = left;  
        }else{  
            swap = array[left] > array[right] ? left : right;  
        }  
    }  
  
    if(swap == left) {  
        median = array[index];  
        array[index] = array[left];  
        array[left] = median;  
    }else{  
        median = array[index];  
        array[index] = array[right];  
        array[right] = median;  
    }  
  
    return swap;  
}  
  
STATUS adjust_leaf_position(int array[], int index)  
{  
    int median = 0;  
    if(array[index] > array[index << 1])  
        return TRUE;  
  
    median = array[index];  
    array[index] = array[index << 1];  
    array[index << 1] = median;  
    return FALSE;  
}  

f）堆排序算法介绍完毕，创建测试用例验证

static void test1()  
{  
    int array[] = {1};  
    heap_sort(array, sizeof(array)/sizeof(int));  
}  
  
static void test2()  
{  
    int array[] = {2, 1};  
    heap_sort(array, sizeof(array)/sizeof(int));  
    assert(1 == array[0]);  
    assert(2 == array[1]);  
}  
  
static void test3()  
{  
    int array[] = {3, 2, 1};  
    heap_sort(array, sizeof(array)/sizeof(int));  
    assert(1 == array[0]);  
    assert(2 == array[1]);  
    assert(3 == array[2]);  
}  
  
static void test4()  
{  
    int array[] = {2, 3, 1};  
    heap_sort(array, sizeof(array)/sizeof(int));  
    assert(1 == array[0]);  
    assert(2 == array[1]);  
    assert(3 == array[2]);  
}  
  
static void test5()  
{  
    int array[] = {5,3, 4, 1};  
    heap_sort(array, sizeof(array)/sizeof(int));  
    assert(1 == array[0]);  
    assert(3 == array[1]);  
    assert(4 == array[2]);  
    assert(5 == array[3]);  
}  
  
static void test6()  
{  
    int array[] = {2, 3,6, 8, 7};  
    heap_sort(array, sizeof(array)/sizeof(int));  
    assert(2 == array[0]);  
    assert(3 == array[1]);  
    assert(6 == array[2]);  
    assert(7 == array[3]);  
    assert(8 == array[4]);  
}  
  
static void test7()  
{  
    int array[] = {3,4,2,7,1,9,8,6,5};  
    heap_sort(array, sizeof(array)/sizeof(int));  
    assert(1 == array[0]);  
    assert(2 == array[1]);  
    assert(3 == array[2]);  
    assert(4 == array[3]);  
    assert(5 == array[4]);  
    assert(6 == array[5]);  
    assert(7 == array[6]);  
    assert(8 == array[7]);  
    assert(9 == array[8]);  
}