How should I practice Hierarchical Permission Check?

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

Is Hierarchical Permission Check associated with eBay?

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

Hierarchical Permission Check

eBay● MediumFULLTIMEONSITE INTERVIEW

Problem statement

A company stores its permissions as a hierarchy. Each row hierarchy[i] = [parent, child] says that permission child sits directly under permission parent. Every permission has at most one parent, so the hierarchy is a forest of trees.

A user holds the permissions listed in granted. Holding a permission also gives the user every permission below it in the hierarchy: its children, their children, and so on. Holding a permission never gives the user anything above it.

A permission name that does not appear in hierarchy has no parent and no children. The user has such a permission only when it is listed in granted.

For each name in queries, decide whether the user has that permission. Return an array of booleans in the same order as queries.

granted and queries may contain repeated names.

Function

checkPermissions(hierarchy: String[][], granted: String[], queries: String[]) → boolean[]

Examples

Example 1

hierarchy = [["admin","billing"],["admin","users"],["billing","refunds"],["users","invite"]]granted = ["billing"]queries = ["refunds","billing","admin","invite"]return = [true,true,false,false]

The user holds billing. Its only child is refunds, so the user has billing and refunds.

admin is the parent of billing. A grant never moves up, so the answer is false.
invite sits under users, which is a different branch, so the answer is false.

Example 2

hierarchy = [["orders","view_orders"],["orders","edit_orders"],["reports","export"]]granted = ["orders","audit"]queries = ["edit_orders","audit","export","delete_all"]return = [true,true,false,false]

edit_orders is a child of the granted orders, so it is covered.

audit is not in the hierarchy, but it is granted directly, so the answer is true.
export sits under reports, which the user does not hold.
delete_all is neither in the hierarchy nor granted, so the answer is false.

Example 3

hierarchy = [["a","b"],["b","c"],["c","d"]]granted = ["c","c"]queries = ["d","c","b","a","d"]return = [true,true,false,false,true]

The chain is a → b → c → d. The user holds c twice, which counts the same as holding it once.

The user has c and d, but not b or a, which are above c. The repeated query d gets the same answer both times.

Constraints

0 <= hierarchy.length <= 400
hierarchy[i].length == 2
0 <= granted.length <= 300
1 <= queries.length <= 400
Every permission name has 1 to 20 characters, and each character is a lowercase English letter or an underscore.
Every row has parent != child.
No permission appears as the child in more than one row, and the rows contain no cycle, so the hierarchy is a forest.