solution: maximum-depth-of-binary-tree

Author: wozlsla

maximum-depth-of-binary-tree/wozlsla.py

@@ -0,0 +1,59 @@
+"""
+# Intuition
+트리 전체 순회
+
+# Approach
+-
+
+# Complexity
+time : O(N)
+space : O(N)
+"""
+
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+
+
+# Stack (top-down)
+class Solution:
+    def maxDepth(self, root: Optional[TreeNode]) -> int:
+
+        # edge case
+        if not root:
+            return 0
+
+        max_depth = 0
+        stack = [(root, 1)]
+
+        while stack:
+            node, depth = stack.pop()
+
+            max_depth = max(depth, max_depth)  # update depth
+
+            if node.left:
+                stack.append((node.left, depth + 1))
+            if node.right:
+                stack.append((node.right, depth + 1))
+
+        return max_depth
+
+
+""" 재귀 (bottom-top)
+# max_depth : 현재 노드를 기준으로, 좌측과 우측 자식 트리 중 max_depth가 큰 값을 선택해 + 1
+
+class Solution:
+    def maxDepth(self, root: Optional[TreeNode]) -> int:
+
+        # 기저조건
+        if not root:
+            return 0
+
+        return 1 + max(
+            self.maxDepth(root.left),
+            self.maxDepth(root.right),
+        )
+"""