Create 104-Maximum-Depth-of-Binary-Tree.py

Author: neetcode-gh

104-Maximum-Depth-of-Binary-Tree.py

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+# RECURSIVE DFS
+class Solution:
+    def maxDepth(self, root: TreeNode) -> int:
+        if not root:
+            return 0
+        
+        return 1 + max(self.maxDepth(root.left), self.maxDepth(root.right))
+
+# ITERATIVE DFS   
+class Solution:
+    def maxDepth(self, root: TreeNode) -> int:
+        stack = [[root, 1]]
+        res = 0
+        
+        while stack:
+            node, depth = stack.pop()
+        
+            if node:
+                res = max(res, depth)
+                stack.append([node.left, depth + 1])
+                stack.append([node.right, depth + 1])
+        return res
+
+# BFS
+class Solution:
+    def maxDepth(self, root: TreeNode) -> int:
+        if not root:
+            return 0
+        
+        level = 0
+        q = deque([root])
+        while q:
+            
+            for i in range(len(q)):
+                node = q.popleft()
+                if node.left:
+                    q.append(node.left)
+                if node.right:
+                    q.append(node.right)
+            level += 1
+        return level