331. Verify Preorder Serialization of a Binary Tree LeetCode Solution

Minimum Cost to Merge Stones

Verify Preorder Serialization of a Binary Tree One way to serialize a binary tree is to use preorder traversal. When we encounter a non-null node, we record the node’s value. If it is a null node, we record using a sentinel value such as '#'.

For example, the above binary tree can be serialized to the string "9,3,4,#,#,1,#,#,2,#,6,#,#", where '#' represents a null node.

Given a string of comma-separated values preorder, return true if it is a correct preorder traversal serialization of a binary tree.

It is guaranteed that each comma-separated value in the string must be either an integer or a character '#' representing null pointer.

You may assume that the input format is always valid.

  • For example, it could never contain two consecutive commas, such as "1,,3".

Note: You are not allowed to reconstruct the tree.

Example 1:

Input: preorder = "9,3,4,#,#,1,#,#,2,#,6,#,#"
Output: true

Example 2:

Input: preorder = "1,#"
Output: false

Example 3:

Input: preorder = "9,#,#,1"
Output: false


  • 1 <= preorder.length <= 104
  • preorder consist of integers in the range [0, 100] and '#' separated by commas ','.

Verify Preorder Serialization of a Binary Tree Solutions

Time: O(n)
Space: O(n)


 Will be updated Soon


 Will be updated Soon


  Will be updated Soon

Watch Tutorial

Checkout more Solutions here

Leave a Comment

Your email address will not be published. Required fields are marked *