max depth of bin tree sol

Author: dylan-jung

maximum-depth-of-binary-tree/dylan-jung.cpp

@@ -0,0 +1,25 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
+ * };
+ */
+class Solution {
+public:
+    int dfs(TreeNode* root, int depth) {
+        int ret = depth;
+        if(root->left) ret = max(ret, dfs(root->left, depth+1));
+        if(root->right) ret = max(ret, dfs(root->right, depth+1));
+        return ret;
+    }
+
+    int maxDepth(TreeNode* root) {
+        if(!root) return 0;
+        return dfs(root, 1);
+    }
+};