How should I practice N-Ary Tree BFS Codec?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Google onsite interview problems in FastPrep.

Is N-Ary Tree BFS Codec associated with Google?

FastPrep tags this as a Google onsite interview coding practice problem when the problem catalog has that company and stage context.

N-Ary Tree BFS Codec

Google● HardINTERNONSITE INTERVIEW

Learn

Problem statement

Implement both directions of a codec for ordered N-ary trees with signed integer node values. Process each row of operations in order and return one result per row.

["SERIALIZE", tree] converts canonical tree text into the breadth-first wire format below.
["DESERIALIZE", data] converts valid wire data into canonical tree text.

Canonical tree text

An empty tree is the empty string. A leaf is its decimal value. A non-leaf is its value followed by its children in parentheses, separated by commas. Child order is significant. For example, 1(3(5,6),2,4) has root 1 with children 3, 2, and 4.

Breadth-first wire format

An empty tree is again the empty string. A nonempty encoding begins with the root value. Later levels are separated by |. Within a later level, list each parent's child values from left to right and terminate that parent's child list with #. Parents are processed in the previous level's left-to-right order. Omit a final level that would contain only # markers.

For example, 1(3(5,6),2,4) serializes as 1|3,2,4,#|5,6,#,#,#. In the last segment, the first # closes node 3's children, and the remaining markers record that nodes 2 and 4 have no children.

Function

transformNaryBfsCodec(operations: String[][]) → String[]

Examples

Example 1

operations = [["SERIALIZE","1(3(5,6),2,4)"],["DESERIALIZE","7|8,9,10,#|#,11,#,#"]]return = ["1|3,2,4,#|5,6,#,#,#","7(8,9(11),10)"]

The first operation writes the tree level by level and uses # to close each parent's child list. In the second operation, node 9 is the only child on its level that receives a child.

Example 2

operations = [["SERIALIZE","42"],["DESERIALIZE","-1|2,3,#"]]return = ["42","-1(2,3)"]

A single node needs no later level. The second wire string gives the root two leaf children.

Constraints

1 <= operations.length <= 200.
Every operation has exactly two strings and uses SERIALIZE or DESERIALIZE.
Every supplied tree text and wire string is valid under the stated grammar.
Each tree contains at most 5000 nodes.
Every node value is a signed 32-bit integer.
The total number of nodes across all operations is at most 20000.