Grokking the Coding Interview: Patterns for Coding Questions
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Level Order Successor (easy)
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Problem Statement

Given a root of the binary tree and an integer key, find the level order successor of the node containing the given key as a value in the tree.

The level order successor is the node that appears right after the given node in the level order traversal.

Examples

Example 1

  • Input: root = [1, 2, 3, 4, 5], key = 3
Image
  • Output: 4
  • Explanation: The level-order traversal of the tree is [1, 2, 3, 4, 5]. The successor of 3 in this order is 4.

Example 2

  • Input: root = [12, 7, 1, 9, null, 10, 5], key = 9
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  • Output: 10
  • Explanation: The level-order traversal of the tree is [12, 7, 1, 9, 10, 5]. The successor of 9 in this order is 10.

Example 3

  • Input: root = [12, 7, 1, 9, null, 10, 5], key = 12
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  • Output: 7
  • Explanation: The level-order traversal of the tree is [12, 7, 1, 9, 10]. The successor of 12 in this order is 7.

Constraints:

  • The number of nodes in the tree is in the range [0, 10<sup>5</sup>].
  • -1000 <= Node.val <= 1000

Try it yourself

Try solving this question here:

Python3
Python3
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