添加（0450.删除二叉搜索树中的节点.md）：增加typescript版本

problems/0450.删除二叉搜索树中的节点.md

@@ -518,6 +518,70 @@ var deleteNode = function (root, key) {
 }
 ```
 
+## TypeScript
+
+> 递归法：
+
+```typescript
+function deleteNode(root: TreeNode | null, key: number): TreeNode | null {
+    if (root === null) return null;
+    if (root.val === key) {
+        if (root.left === null && root.right === null) return null;
+        if (root.left === null) return root.right;
+        if (root.right === null) return root.left;
+        let curNode: TreeNode = root.right;
+        while (curNode.left !== null) {
+            curNode = curNode.left;
+        }
+        curNode.left = root.left;
+        return root.right;
+    }
+    if (root.val > key) root.left = deleteNode(root.left, key);
+    if (root.val < key) root.right = deleteNode(root.right, key);
+    return root;
+};
+```
+
+> 迭代法：
+
+```typescript
+function deleteNode(root: TreeNode | null, key: number): TreeNode | null {
+    function removeTargetNode(root: TreeNode): TreeNode | null {
+        if (root.left === null && root.right === null) return null;
+        if (root.right === null) return root.left;
+        if (root.left === null) return root.right;
+        let curNode: TreeNode | null = root.right;
+        while (curNode.left !== null) {
+            curNode = curNode.left;
+        }
+        curNode.left = root.left;
+        return root.right;
+    }
+    let preNode: TreeNode | null = null,
+        curNode: TreeNode | null = root;
+    while (curNode !== null) {
+        if (curNode.val === key) break;
+        preNode = curNode;
+        if (curNode.val > key) {
+            curNode = curNode.left;
+        } else {
+            curNode = curNode.right;
+        }
+    }
+    if (curNode === null) return root;
+    if (preNode === null) {
+        // 删除头节点
+        return removeTargetNode(curNode);
+    }
+    if (preNode.val > key) {
+        preNode.left = removeTargetNode(curNode);
+    } else {
+        preNode.right = removeTargetNode(curNode);
+    }
+    return root;
+};
+```
+
 
 
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