solve: maximum depth of binary tree

Author: sounmind

maximum-depth-of-binary-tree/evan.js

@@ -0,0 +1,39 @@
+/**
+ * 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 {number}
+ */
+var maxDepth = function (root) {
+  if (root === null) {
+    return 0;
+  }
+
+  const leftDepth = maxDepth(root.left);
+  const rightDepth = maxDepth(root.right);
+
+  return Math.max(leftDepth, rightDepth) + 1;
+};
+
+/**
+ * Time Complexity: O(n), where n is the number of nodes in the binary tree.
+ * Reason:
+ *  the function visits each node exactly once in order to compute the depth of the tree,
+ *  which ensures that each node is processed a single time.
+ *
+ * Space Complexity: O(h), where h is the height of the binary tree.
+ * Reason:
+ *   The recursion stack used during the depth-first traversal.
+ *
+ *   In the worst case, where the tree is completely unbalanced,
+ *   the height h can be equal to the number of nodes n, leading to a space complexity of O(n).
+ *
+ *   In the best case, where the tree is balanced, the height h is log(n),
+ *   leading to a space complexity of O(log(n)).
+ */