How should I practice Topological Sort for Ads Tasks?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Netflix phone screen problems in FastPrep.

Is Topological Sort for Ads Tasks associated with Netflix?

FastPrep tags this as a Netflix phone screen coding practice problem when the problem catalog has that company and stage context.

Topological Sort for Ads Tasks

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Problem statement

You are given numTasks tasks labeled from 0 to numTasks - 1 and a list of prerequisite edges. Each edge [before, after] means task before must be completed before task after.

Return one valid order to complete all tasks. If more than one task is available at the same time, choose the smaller task id first so the result is deterministic. If it is impossible to complete all tasks because the dependency graph contains a cycle, return an empty array.

Function

findTaskOrder(numTasks: int, edges: int[][]) → int[]

Examples

Example 1

numTasks = 4edges = [[0, 1], [0, 2], [1, 3], [2, 3]]return = [0, 1, 2, 3]

Task 0 unlocks tasks 1 and 2. The smaller available id is chosen first.

Example 2

numTasks = 2edges = [[0, 1], [1, 0]]return = []

The two tasks depend on each other, so no valid topological order exists.

Constraints

0 <= before, after < numTasks
Use topological sorting with cycle detection.
When multiple tasks have in-degree zero, choose the smallest task id first.