update 0450.删除二叉搜索树中的节点，增加js的迭代写法

problems/0450.删除二叉搜索树中的节点.md

@@ -485,6 +485,41 @@ var deleteNode = function (root, key) {
 };
 ```
 
+迭代
+``` javascript
+var deleteNode = function (root, key) {
+    const deleteOneNode = target => {
+        if (!target) return target
+        if (!target.right) return target.left
+        let cur = target.right
+        while (cur.left) {
+            cur = cur.left
+        }
+        cur.left = target.left
+        return target.right
+    }
+
+    if (!root) return root
+    let cur = root
+    let pre = null
+    while (cur) {
+        if (cur.val === key) break
+        pre = cur
+        cur.val > key ? cur = cur.left : cur = cur.right
+    }
+    if (!pre) {
+        return deleteOneNode(cur)
+    }
+    if (pre.left && pre.left.val === key) {
+        pre.left = deleteOneNode(cur)
+    }
+    if (pre.right && pre.right.val === key) {
+        pre.right = deleteOneNode(cur)
+    }
+    return root
+}
+```
+
 
 
 -----------------------