Update 0450.删除二叉搜索树中的节点.md JavaScript递归版本

problems/0450.删除二叉搜索树中的节点.md

@@ -456,31 +456,42 @@ func deleteNode(root *TreeNode, key int) *TreeNode {
  * @param {number} key
  * @return {TreeNode}
  */
-var deleteNode = function (root, key) {
+var deleteNode = function(root, key) {
-    if (root === null)
+    if (!root) return null;
-        return root;
+    if (key > root.val) {
-    if (root.val === key) {
-        if (!root.left)
-            return root.right;
-        else if (!root.right)
-            return root.left;
-        else {
-            let cur = root.right;
-            while (cur.left) {
-                cur = cur.left;
-            }
-            cur.left = root.left;
-            root = root.right;
-            delete root;
-            return root;
-        }
-    }
-    if (root.val > key)
-        root.left = deleteNode(root.left, key);
-    if (root.val < key)
         root.right = deleteNode(root.right, key);
-    return root;
+        return root;
+    } else if (key < root.val) {
+        root.left = deleteNode(root.left, key);
+        return root;
+    } else {
+        // 场景1: 该节点是叶节点
+        if (!root.left && !root.right) {
+            return null
+        }
+        // 场景2: 有一个孩子节点不存在
+        if (root.left && !root.right) {
+            return root.left;
+        } else if (root.right && !root.left) {
+            return root.right;
+        }
+        // 场景3: 左右节点都存在
+        const rightNode = root.right;
+        // 获取最小值节点
+        const minNode = getMinNode(rightNode);
+        // 将待删除节点的值替换为最小值节点值
+        root.val = minNode.val;
+        // 删除最小值节点
+        root.right = deleteNode(root.right, minNode.val);
+        return root;
+    }
 };
+function getMinNode(root) {
+    while (root.left) {
+        root = root.left;
+    }
+    return root;
+}
 ```
 
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