Create 124-Binary-Tree-Maximum-Path-Sum.py

Author: neetcode-gh

124-Binary-Tree-Maximum-Path-Sum.py

@@ -0,0 +1,26 @@
+# 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:
+    def maxPathSum(self, root: TreeNode) -> int:
+        res = [root.val]
+        
+        # return max path sum without split
+        def dfs(root):
+            if not root:
+                return 0
+            
+            leftMax = dfs(root.left)
+            rightMax = dfs(root.right)
+            leftMax = max(leftMax, 0)
+            rightMax = max(rightMax, 0)
+            
+            # compute max path sum WITH split
+            res[0] = max(res[0], root.val + leftMax + rightMax)
+            return root.val + max(leftMax, rightMax)
+        
+        dfs(root)
+        return res[0]