add: maximum depth of binary tree solution

Author: JEONGBEOMKO

maximum-depth-of-binary-tree/JEONGBEOMKO.java

@@ -0,0 +1,40 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode() {}
+ *     TreeNode(int val) { this.val = val; }
+ *     TreeNode(int val, TreeNode left, TreeNode right) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+
+
+class Solution {
+    /*
+    time complexity: O(n)
+    space complexity: O(h)
+     */
+    int maxDepth = 0;
+
+    public int maxDepth(TreeNode root) {
+        depthChk(root, 0);
+        return maxDepth;
+    }
+
+    public void depthChk(TreeNode node, int depth) {
+        if (node == null) {
+            maxDepth = Math.max(depth, maxDepth);
+            return;
+        }
+
+        // 트리의 좌우 탐색
+        depthChk(node.left, depth + 1);
+        depthChk(node.right, depth + 1);
+    }
+}