maximum-depth-of-bt py3

0104_maximum-depth-of-binary-tree/python3/dfs-pre-order-global.py

@@ -0,0 +1,27 @@
+# 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
+class Solution:
+    maxDepthValue = 0
+    
+    def maxDepth(self, root: Optional[TreeNode]) -> int:
+        '''
+        Recursive DFS pre-order but storing max globally
+        '''
+        def findMax(node, depth):
+            if node is None: return None
+            
+            currDepth = depth + 1
+            self.maxDepthValue = max(currDepth, self.maxDepthValue)
+            findMax(node.left, currDepth)
+            findMax(node.right, currDepth)
+        
+        findMax(root, 0)
+        
+        return self.maxDepthValue

0104_maximum-depth-of-binary-tree/python3/dfs-pre-order-oneliner.py

@@ -0,0 +1,17 @@
+# 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
+class Solution:
+    maxDepthValue = 0
+    
+    def maxDepth(self, root: Optional[TreeNode]) -> int:
+        '''
+        Recursive DFS
+        '''
+        return 0 if root is None else 1 + max(self.maxDepth(root.left), self.maxDepth(root.right))