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我有以下工作代码,红黑树旋转。指针交换奇怪
void BalancedTree::rotateLeft(Node* & x){
37 Node* y = x->right;
38
39 x->right = y->left;//slice y's left child
40 x->right->parent = x;
41
42 y->left = x;//switch x and y's parentship
43 Node* xp = x->parent;//for some reason, y->parent = x->parent causes logic
errors.
44 x->parent = y;
45 y->parent = xp;
46
47 if (y->parent == nil) root = y;//fix grandparent
48 else if (y->parent->parent->left == x) y->parent->parent->left = y;
49 else y->parent->parent->right = y;
50 }
当线43和45是由替换(保持44)
y->parent = x->parent
或者,只是交换线44和45,节点指针的用x含量改变。我想要做的就是:改变Node中的指针(父)(由y指向),并让它指向x的父节点。
节点结构为:
struct Node{
Node* parent;
Node* left;
Node* right;
int value;
};
我这么想吗?指针的基本属性?
编辑:页313 Cormen的算法导论
LEFT-ROTATE(T, x)
1 y = x.right
2 x.right = y.left
3 if y.left != T.nil
4 y.left.p = x
5 y.p = x.p
6 if x.p == T.nil
7 T.root = y
8 elseif x == x.p.left
9 x.p.left = y
10 else x.p.right = y
11 y.left = x
12 x.p = y
EDIT2:这里是不工作的代码:
36 void BalancedTree::rotateLeft(Node* & x){
37 Node* y = x->right;
38
39 x->right = y->left;//slice y's left child
40 x->right->parent = x;
41
42 y->left = x;//switch x and y's parentship
43 y->parent = x->parent;
44 x->parent = y;
45
46
47 if (y->parent == nil) root = y;//fix grandparent
48 else if (y->parent->parent->left == x) y->parent->parent->left = y;
49 else y->parent->parent->right = y;
50 }
您不是描述所做的更改,而是显示您试图用来移除'xp'的确切代码。 –
我不理解编辑。你的代码与它完全无关。它根本不匹配。你为什么不仔细实施Cormen的算法? –