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Algorithm to get maximum path sum of a binary tree. #9414

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Algorithm to get maximum path sum of a binary tree.
jahir-raihan Oct 2, 2023
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commit 49633c2fd2ef00d791cf32bd2e71171aac9e595b
5 changes: 1 addition & 4 deletions data_structures/binary_tree/binary_tree_maximum_path_sum.py
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Expand Up @@ -26,7 +26,6 @@ def __init__(self, val: int) -> None:


class GetMaxPathSum:
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@cclauss cclauss Oct 2, 2023 •
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This is a custom class only designed the get the sum.

I would prefer to see a generic BinaryTree class that:

  1. has a self.root_node
  2. implements .__iter__() instead of .traverse().
  3. delivers the solution with the simple line sum(binary_tree)
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@cclauss cclauss Oct 2, 2023

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Like this but for a BinaryTree instead of a LinkedList.
https://github.com/TheAlgorithms/Python/blob/master/data_structures/linked_list/reverse_k_group.py#L13
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@cclauss cclauss Oct 2, 2023

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Perhaps 3. is not possible for this problem.
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@jahir-raihan jahir-raihan Oct 2, 2023

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@cclauss I'm bit confused about iter(), as traverse recursively takes maximum from left and right subtree, how can I implement that. Please give me hint on it.
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Yes. Now I see the difficulties. Please make the BinaryTree and make a .traverse() method that yields the values.
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@jahir-raihan jahir-raihan Oct 2, 2023

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@cclauss As the algorithm traverses all the nodes recursively, if we try to yield values of nodes, we'll end up yielding all the nodes. Because yield will go over all nodes where's our algorithm only requires those nodes that makes up the maximum value. Please correct me if i'm wrong.
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@cclauss cclauss Oct 2, 2023

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You are probably right.
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@jahir-raihan jahir-raihan Oct 3, 2023

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@cclauss Hello, My PR getting out of the list now. Can you hear me back please how can I improve more.

r"""

GetMaxPathSum takes root node of a tree as initial argument.
Expand Down Expand Up @@ -67,7 +66,6 @@ def __init__(self, root) -> None:
self.root = root

def traverse(self, root: TreeNode | None) -> int:

"""
Returns maximum path sum by recursively taking max_path_sum from left
and max_path_sum from right if current Node has a left or right Node.
Expand All @@ -88,7 +86,6 @@ def traverse(self, root: TreeNode | None) -> int:
return root.val + max(right_sum, left_sum)

def max_path_sum(self) -> int:

"""
Driver method to get max_path_sum by calling traverse method.
:return max_path_sum:
Expand Down Expand Up @@ -124,7 +121,7 @@ def construct_tree() -> TreeNode:
return root


if __name__ == '__main__':
if __name__ == "__main__":
import doctest

tree = GetMaxPathSum(construct_tree())
Expand Down