feat: 문제풀이 추가

Author: JEONGHWANMIN

invert-binary-tree/hwanmini.js

@@ -0,0 +1,30 @@
+// 시간복잡도: O(n)
+// 공간복잡도: O(n)
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {TreeNode}
+ */
+var invertTree = function(root) {
+    if (!root) return null;
+
+    const left = root.left
+    const right = root.right
+
+    root.left = right
+    root.right = left
+
+
+    invertTree(left)
+    invertTree(right)
+
+    return root
+};