Merge pull request #576 from Spongecaptain/patch-4

Update 0450.删除二叉搜索树中的节点.md

problems/0450.删除二叉搜索树中的节点.md

@@ -320,6 +320,7 @@ class Solution:
 
 Go：
 ```Go
+// 递归版本
 func deleteNode(root *TreeNode, key int) *TreeNode {
     if root==nil{
         return nil
@@ -356,6 +357,51 @@ func deleteNode1(root *TreeNode)*TreeNode{
     root.Left=deleteNode1(root.Left)
     return root
 }
+// 迭代版本
+func deleteOneNode(target *TreeNode) *TreeNode {
+	if target == nil {
+		return target
+	}
+	if target.Right == nil {
+		return target.Left
+	}
+	cur := target.Right
+	for cur.Left != nil {
+		cur = cur.Left
+	}
+	cur.Left = target.Left
+	return target.Right
+}
+func deleteNode(root *TreeNode, key int) *TreeNode {
+	// 特殊情况处理
+	if root == nil {
+		return root
+	}
+	cur := root
+	var pre *TreeNode
+	for cur != nil {
+		if cur.Val == key {
+			break
+		}
+		pre = cur
+		if cur.Val > key {
+			cur = cur.Left
+		} else {
+			cur = cur.Right
+		}
+	}
+	if pre == nil {
+		return deleteOneNode(cur)
+	}
+	// pre 要知道是删除左孩子还有右孩子
+	if pre.Left != nil && pre.Left.Val == key {
+		pre.Left = deleteOneNode(cur)
+	}
+	if pre.Right != nil && pre.Right.Val == key {
+		pre.Right = deleteOneNode(cur)
+	}
+	return root
+}
 ```
 
 JavaScript版本