Merge branch 'master' of github.com:KingArthur0205/leetcode-master

nowsoar · Jan 26, 2023 · b7c8ba8 · b7c8ba8
2 parents 9d02c76 + fdfa50b
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diff --git a/problems/0108.将有序数组转换为二叉搜索树.md b/problems/0108.将有序数组转换为二叉搜索树.md
@@ -352,6 +352,38 @@ class Solution:
         return mid_root
 ```
 
+**迭代**（左闭右开）
+```python
+class Solution:
+    def sortedArrayToBST(self, nums: List[int]) -> Optional[TreeNode]:
+        if len(nums) == 0: return None
+        root = TreeNode()  # 初始化
+        nodeSt = [root]
+        leftSt = [0]
+        rightSt = [len(nums)]
+
+        while nodeSt:
+            node = nodeSt.pop()  # 处理根节点
+            left = leftSt.pop()
+            right = rightSt.pop()
+            mid = left + (right - left) // 2
+            node.val = nums[mid]
+
+            if left < mid:  # 处理左区间
+                node.left = TreeNode()
+                nodeSt.append(node.left)
+                leftSt.append(left)
+                rightSt.append(mid)
+
+            if right > mid + 1:  # 处理右区间
+                node.right = TreeNode()
+                nodeSt.append(node.right)
+                leftSt.append(mid + 1)
+                rightSt.append(right)
+
+        return root
+```
+
 ## Go 
 
 递归（隐含回溯）

diff --git a/problems/0450.删除二叉搜索树中的节点.md b/problems/0450.删除二叉搜索树中的节点.md
@@ -348,6 +348,24 @@ class Solution:
         return root
 ```
 
+**普通二叉树的删除方式**
+```python
+class Solution:
+    def deleteNode(self, root: Optional[TreeNode], key: int) -> Optional[TreeNode]:
+        if not root: return root
+        if root.val == key:
+            if not root.right:  # 这里第二次操作目标值：最终删除的作用
+                return root.left
+            tmp = root.right
+            while tmp.left:
+                tmp = tmp.left
+            root.val, tmp.val = tmp.val, root.val  # 这里第一次操作目标值：交换目标值其右子树最左面节点。
+
+        root.left = self.deleteNode(root.left, key)
+        root.right = self.deleteNode(root.right, key)
+        return root
+```
+
 **迭代法**
 ```python
 class Solution:

diff --git a/problems/0669.修剪二叉搜索树.md b/problems/0669.修剪二叉搜索树.md
@@ -299,6 +299,32 @@ class Solution:
             return root
 ```
 
+**迭代**
+```python
+class Solution:
+    def trimBST(self, root: Optional[TreeNode], low: int, high: int) -> Optional[TreeNode]:
+        if not root: return root
+        # 处理头结点，让root移动到[L, R] 范围内，注意是左闭右开
+        while root and (root.val < low or root.val > high):
+            if root.val < low:  # 小于L往右走
+                root = root.right
+            else:  # 大于R往左走
+                root = root.left
+        # 此时root已经在[L, R] 范围内，处理左孩子元素小于L的情况
+        cur = root
+        while cur:
+            while cur.left and cur.left.val < low:
+                cur.left = cur.left.right
+            cur = cur.left
+        # 此时root已经在[L, R] 范围内，处理右孩子大于R的情况
+        cur = root
+        while cur:
+            while cur.right and cur.right.val > high:
+                cur.right = cur.right.left
+            cur = cur.right
+        return root
+```
+
 ## Go 
 
 ```go