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Sum of the Bottom Level

Medium
You get the root of a binary tree. Find the nodes that lie farthest from the root and return the sum of their values.
Example 1
root=tree_node([3, 9, 20, None, None, 15, 7]) → 22

The deepest level is level 2, holding 15 and 7. Their sum is 22.

Example 2
root=tree_node([4, None, 8, 2, 5]) → 7

The root has only a right child 8, whose children are 2 and 5. They are the deepest: 2 + 5 = 7.

Example 3
root=tree_node([10]) → 10

The only node is the deepest level by itself.

Constraints
  • The tree has between 1 and 10⁴ nodes
  • 1 ≤ Node.val ≤ 100
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Topics
TreeDepth-First SearchBreadth-First SearchBinary Tree
Similar problemsThe Tree Seen From the Right MediumTree Columns, Top Down MediumFirst Value on the Lowest Row MediumLargest Value on Each Tree Level MediumInsert a Tree Level Medium
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Input
root=tree_node([3, 9, 20, None, None, 15, 7])
Expected
22

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