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Fix the return type of binary search tree and avl tree

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krahets
2023-04-14 05:47:20 +08:00
parent 9c9c8b7574
commit f7ae9c8a02
24 changed files with 247 additions and 451 deletions
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42
codes/csharp/chapter_tree/binary_search_tree.cs
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@ -57,16 +57,16 @@ class BinarySearchTree
}
/* 插入节点 */
public TreeNode? insert(int num)
public void insert(int num)
{
// 若树为空，直接提前返回
if (root == null) return null;
if (root == null) return;
TreeNode? cur = root, pre = null;
// 循环查找，越过叶节点后跳出
while (cur != null)
{
// 找到重复节点，直接返回
if (cur.val == num) return null;
if (cur.val == num) return;
pre = cur;
// 插入位置在 cur 的右子树中
if (cur.val < num) cur = cur.right;
@ -81,15 +81,14 @@ class BinarySearchTree
if (pre.val < num) pre.right = node;
else pre.left = node;
}
return node;
}
/* 删除节点 */
public TreeNode? remove(int num)
public void remove(int num)
{
// 若树为空，直接提前返回
if (root == null) return null;
if (root == null) return;
TreeNode? cur = root, pre = null;
// 循环查找，越过叶节点后跳出
while (cur != null)
@ -103,7 +102,7 @@ class BinarySearchTree
else cur = cur.left;
}
// 若无待删除节点，则直接返回
if (cur == null || pre == null) return null;
if (cur == null || pre == null) return;
// 子节点数量 = 0 or 1
if (cur.left == null || cur.right == null)
{
@ -123,29 +122,16 @@ class BinarySearchTree
else
{
// 获取中序遍历中 cur 的下一个节点
TreeNode? nex = getInOrderNext(cur.right);
if (nex != null)
TreeNode? tmp = cur.right;
while (tmp.left != null)
{
int tmp = nex.val;
// 递归删除节点 nex
remove(nex.val);
// 将 nex 的值复制给 cur
cur.val = tmp;
tmp = tmp.left;
}
// 递归删除节点 tmp
remove(tmp.val);
// 用 tmp 覆盖 cur
cur.val = tmp.val;
}
return cur;
}
/* 获取中序遍历中的下一个节点（仅适用于 root 有左子节点的情况） */
private TreeNode? getInOrderNext(TreeNode? root)
{
if (root == null) return root;
// 循环访问左子节点，直到叶节点时为最小节点，跳出
while (root.left != null)
{
root = root.left;
}
return root;
}
}
@ -165,7 +151,7 @@ public class binary_search_tree
Console.WriteLine("\n查找到的节点对象为 " + node + "，节点值 = " + node.val);
/* 插入节点 */
node = bst.insert(16);
bst.insert(16);
Console.WriteLine("\n插入节点 16 后，二叉树为\n");
PrintUtil.PrintTree(bst.getRoot());