我有一个具有以下定义的类,
class BinomialNode
{
public int key; // The key value
public int x_point; // x co-ordinate for drawing
public int y_point; // y co-ordinate for drawing
public int degree; // number of siblings/children for current node
public BinomialNode parent;
public BinomialNode child;
public BinomialNode sibling;
...
}
我们在大学里学习二项式堆,我已经在代码中实现了合并和插入算法。至少,当我暂停 Visual Studio 并查看“Locals”时(通过将鼠标悬停在变量上),我可以看到预期的数据。
作为一个实验,我在标准的“二项式节点”中添加了 2 个额外的变量。它们是 x_point 和 y_point。现在在程序执行期间我看到了这个,
请注意我在上面指出的区域。它应该代表同一个节点,但正如我们所见,x_point 的值是不同的。(在其他情况下,y_point 不同)
有谁知道为什么会这样?据我了解,如果它代表同一个节点,则数据应该是相同的。但它不是——这意味着它不是同一个节点。这怎么可能?如果我忽略我的“额外” x_point 和 y_point 变量,代码运行完美!事实上,我什至都不知道这是个问题。
从我的代码片段中看不到它,但 x_point 和 y_point 是我在类定义之外编辑的唯一值。其他的,虽然是公开的,但只能从中读取。
编辑:这是我制作的代码,
class BinomialNode
{
public int key; // The key value
public int x_point; // x co-ordinate for drawing
public int y_point; // y co-ordinate for drawing
public int degree; // number of siblings/children for current node
public BinomialNode parent;
public BinomialNode child;
public BinomialNode sibling;
// Binomial Link takes the tree rooted at y and makes it a child of z
private static void Binomial_Link(ref BinomialNode y,ref BinomialNode z)
{
y.parent = z;
y.sibling = z.child;
z.child = y;
z.degree++;
}
// This merges the root lists of H1 and H2 into a single linked list that is sorted
// by degree in increasing order
private static BinomialNode Binomial_Heap_Merge(BinomialNode H1, BinomialNode H2)
{
BinomialNode H = new BinomialNode();
BinomialNode temp = H;
if (H1 == null) // if it's the first insert
{
return H2;
}
while (H1 != null && H2 != null)
{
if (H1.degree < H2.degree)
{
// insert H1 into position
temp.key = H1.key;
temp.x_point = H1.x_point;
temp.y_point = H1.y_point;
temp.child = H1.child;
temp.degree = H1.degree;
temp.sibling = new BinomialNode();
temp = temp.sibling;
// move H1 to the next sibling
H1 = H1.sibling;
}
else
{
// insert H2 into position
temp.key = H2.key;
temp.x_point = H2.x_point;
temp.y_point = H2.y_point;
temp.child = H2.child;
temp.degree = H2.degree;
temp.sibling = new BinomialNode();
temp = temp.sibling;
// move H2 to next sibling
H2 = H2.sibling;
}
}
// one of them hit null, so fill in the rest
while (H1 != null)
{
// insert H1 into position
temp.key = H1.key;
temp.x_point = H1.x_point;
temp.y_point = H1.y_point;
temp.child = H1.child;
temp.degree = H1.degree;
temp.sibling = new BinomialNode();
temp = temp.sibling;
// move H1 to the next sibling
H1 = H1.sibling;
}
while (H2 != null)
{
// insert H2 into position
temp.key = H2.key;
temp.x_point = H2.x_point;
temp.y_point = H2.y_point;
temp.child = H2.child;
temp.degree = H2.degree;
temp.sibling = new BinomialNode();
temp = temp.sibling;
// move H2 to the next sibling
H2 = H2.sibling;
}
// To remove the extra node added,
temp = H;
while (temp != null)
{
if (temp.sibling.key == 0 && temp.sibling.sibling == null && temp.sibling.child == null)
{
// found the extra, now to get rid of it!
temp.sibling = null;
}
temp = temp.sibling;
}
return H; // send back the merged heap
}
// Unites the binomial heaps H1 & H2 and returns resulting heap
public static BinomialNode Binomial_Heap_Union(BinomialNode H1, BinomialNode H2)
{
BinomialNode prev_x, x, next_x;
BinomialNode H = new BinomialNode();
H = Binomial_Heap_Merge(H1, H2);
// simple checks
if (H == null)
{
return H;
}
else
{
prev_x = null;
x = H;
next_x = x.sibling;
}
// now, for the actual merging
while (next_x != null)
{
if ((x.degree != next_x.degree) || (next_x.sibling != null && x.degree == next_x.sibling.degree))
{
prev_x = x;
x = next_x;
}
else if (x.key <= next_x.key)
{
x.sibling = next_x.sibling;
Binomial_Link(ref next_x, ref x);
}
else
{
if (prev_x == null)
{
H = next_x;
}
else
{
prev_x.sibling = x.sibling;
}
Binomial_Link(ref x, ref next_x);
x = next_x;
}
next_x = x.sibling;
}
// now, to return the merged heap
return H;
}
// inserting a key into a heap
public static void Binomial_Heap_Insert(ref BinomialNode H, int x)
{
BinomialNode H_temp = new BinomialNode();
H_temp.key = x;
H_temp.parent = null;
H_temp.degree = 0;
H_temp.sibling = null;
H_temp.child = null;
H = Binomial_Heap_Union(H, H_temp);
}
}
我使用表单窗口从用户那里获取数据以填充堆。输入在这里,
private void button1_Click(object sender, EventArgs e)
{
BinomialNode.Binomial_Heap_Insert(ref B_HEAP1, Int32.Parse(numericUpDown1.Value.ToString()));
// drawing the heap
pictureBox1.Refresh();
int x = 0;
DrawNodeValue(pictureBox1, ref B_HEAP1, ref x, 0);
}
我希望代码不是太糟糕?