Question

我正在尝试在C中实现一个skew堆，但是我的代码没有编译。我不是那种经验丰富的C并且从未在C中创建过任何类型的堆。这就是为什么我不知道如何解决它，我希望有人可以指出我正确的方向。我一直在读关于倾斜堆的文章，这是我到目前为止使用我在网上找到的算法得到的。提前致谢。

typedef struct node
{
int value;
struct node * root;
struct node * leftchild;
struct node * rightchild;
} Node;

struct skewHeap
{
    struct node * root;
};

void skewHeapInit (struct skewHeap * sk)
{
    sk->root = 0;
}

void skewHeapAdd (struct skewHeap *sk)
{
    struct node *n = (struct node *) malloc(sizeof(struct node));
    assert(n != 0);
    n->value = 0;
    n->leftchild = 0;
    n->rightchild = 0;
    line 185. s->root = skewHeapMerge(s->root, n);
}

void skewHeapRemoveFirst (struct skewHeap *sk)
{
    struct node * n = sk->root;
    free(n);
    sk->root = skewHeapMerge(n->leftchild, n->rightchild);
}

line 196. struct node * skewHeapMerge(struct node *left, struct node *right)
{
    struct node *temp = (struct node *) malloc(sizeof(struct node));

    if (left == NULL) 
        return *right;

    if (right == NULL) 
        return *left;

    if (left->value < right-> value)
    {
        temp = left->leftchild;
        left->leftchild = skewHeapMerge(left->rightchild, right);
        left->rightchild = temp;
        return left;
    }
    else
    {
        temp = right->rightchild;
        right->rightchild = skewHeapMerge(right->leftchild, left);
        right->leftchild = temp;
        return right;
    }
}

这些是我目前得到的编辑错误：

program.c: In function ‘skewHeapAdd’:
program.c:185: warning: implicit declaration of function ‘skewHeapMerge’
program.c:185: warning: assignment makes pointer from integer without a cast
program.c: In function ‘skewHeapRemoveFirst’:
program.c:191: warning: assignment makes pointer from integer without a cast
program.c: At top level:
program.c:196: error: conflicting types for ‘skewHeapMerge’
program.c:185: note: previous implicit declaration of ‘skewHeapMerge’ was here
program.c: In function ‘skewHeapMerge’:
program.c:202: error: incompatible types when returning type ‘struct node’ but ‘struct   node *’ was expected
program.c:205: error: incompatible types when returning type ‘struct node’ but ‘struct node *’ was expected

Answer 1

关于编译器错误，

program.c: In function ‘skewHeapAdd’:
program.c:185: warning: implicit declaration of function ‘skewHeapMerge’
program.c:185: warning: assignment makes pointer from integer without a cast

告诉你，skewHeapMerge的原型没有定义skewHeapAdd的范围，因此（编译器显然在C89模式下运行，但幸运的是警告它），编译器假设一个隐式声明返回int的{{1}}类型。

为所有函数添加包含原型的头文件，并在使用或定义这些函数的所有skewHeapMerge文件中添加#include，以便编译器知道函数的类型。

*.c

应该是

行

program.c: In function ‘skewHeapRemoveFirst’:
program.c:191: warning: assignment makes pointer from integer without a cast

其中sk->root = skewHeapMerge(n->leftchild, n->rightchild);是sk->root，但由于struct node*的隐式声明，假设返回skewHeapMerge。

int

这里编译器发现program.c: At top level: program.c:196: error: conflicting types for ‘skewHeapMerge’ program.c:185: note: previous implicit declaration of ‘skewHeapMerge’ was here的定义给出了与隐式声明中的类型冲突的类型。

skewHeapMerge

这是行

program.c: In function ‘skewHeapMerge’:
program.c:202: error: incompatible types when returning type ‘struct node’ but ‘struct   node *’ was expected
program.c:205: error: incompatible types when returning type ‘struct node’ but ‘struct node *’ was expected

你应该返回if (left == NULL) return *right; if (right == NULL) return *left; resp。 right代替left resp。 *right（我起初忽略了这一点）。

*left

中有错误

skewHeapRemoveFirst

在void skewHeapRemoveFirst (struct skewHeap *sk) { struct node * n = sk->root; free(n); sk->root = skewHeapMerge(n->leftchild, n->rightchild); }之后使用n的地方。你必须在该函数中交换最后两行。

并在free

skewHeapMerge

你正在泄露记忆。删除分配，因为如果完全使用

struct node * skewHeapMerge(struct node *left, struct node *right)
{
    struct node *temp = (struct node *) malloc(sizeof(struct node));

    if (left == NULL)
        return *right;

    if (right == NULL)
        return *left;

，则为其分配temp或left->leftchild。

C实现倾斜堆

1 个答案: