maximum-depth-of-binary-tree solution

Author: hyeri0903

maximum-depth-of-binary-tree/hyeri0903.java

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+/**
+ * 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 {
+    public int maxDepth(TreeNode root) {
+        /**
+        문제: 바이너리트리의 maximum depth 구하기
+        조건
+        - 노드의 개수는 0 ~ 10^4
+        - node val 은 -100 ~ 100
+        풀이: dfs 로 depth 구하기
+        - 주어진 트리는 binary tree
+        - time complexity : O(n) , O(log n)
+        - space complexity : O(h)
+         */
+
+
+         if(root == null) return 0;
+
+         int height = dfs(root);
+        return height;
+    }
+
+    int dfs(TreeNode node) {
+        if(node == null) return 0;
+
+        int left = dfs(node.left);
+        int right = dfs(node.right);
+
+        return Math.max(left, right) + 1;
+    }
+}