[ganu] Week 10

invert-binary-tree/gwbaik9717.js

@@ -0,0 +1,33 @@
+// Time complexity: O(n)
+// Space complexity: 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) {
+  const dfs = (current) => {
+    if (!current) {
+      return;
+    }
+
+    const temp = current.left;
+    current.left = current.right;
+    current.right = temp;
+
+    dfs(current.left);
+    dfs(current.right);
+  };
+
+  dfs(root);
+
+  return root;
+};