update: 104

Author: hijiangtao

README.md

@@ -55,6 +55,7 @@ This is the solutions collection of my LeetCode submissions, most of them are pr
 |100|[Same Tree](https://leetcode.com/problems/same-tree/) | [JavaScript](./src/same-tree/res.js)|Easy|
 |101|[Symmetric Tree](https://leetcode.com/problems/symmetric-tree/) | [JavaScript](./src/symmetric-tree/res.js)|Easy|
 |102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/) | [JavaScript](./src/binary-tree-level-order-traversal/res.js)|Medium|
+|104|[Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/) | [JavaScript](./src/maximum-depth-of-binary-tree/res.js)|Easy|
 |107|[Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii/) | [JavaScript](./src/binary-tree-level-order-traversal-ii/res.js)|Easy|
 |111|[Minimum Depth of Binary Tree](https://leetcode.com/problems/minimum-depth-of-binary-tree/) | [JavaScript](./src/minimum-depth-of-binary-tree/res.js)|Easy|
 |120|[Triangle](https://leetcode.com/problems/triangle/) | [JavaScript](./src/triangle/res.js)|Medium|

src/maximum-depth-of-binary-tree/res.js

@@ -0,0 +1,23 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val) {
+ *     this.val = val;
+ *     this.left = this.right = null;
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+var maxDepth = function(root) {
+  if (!root) return 0;
+
+  const getTreeDepth = (element) => {
+    if (!element) return 0;
+    if (element.val !== undefined && !element.left && !element.right) return 1;
+
+    return 1 + Math.max(getTreeDepth(element.left), getTreeDepth(element.right))
+  }
+
+  return 1 + Math.max(getTreeDepth(root.left), getTreeDepth(root.right));
+};

src/same-tree/res.js

@@ -6,6 +6,7 @@
  * }
  */
 /**
+ * DFS
  * @param {TreeNode} p
  * @param {TreeNode} q
  * @return {boolean}