Compute minimal time to finish dependent tasks

## Coding: Task Scheduling With Prerequisites (Parallel Allowed) You have `n` tasks labeled `1..n`. Each task takes **exactly 1 unit of time** to complete. Some tasks have prerequisites. You are given a list of prerequisite pairs `deps`, where each pair `[a, b]` means: - Task `a` must be completed **before** task `b` can start. You can run **any number of tasks in parallel** as long as their prerequisites are satisfied. ### Input - Integer `n`. - 2D array/list `deps` of pairs `[a, b]`. ### Output Return the **minimum total time** (number of time units) required to finish all tasks. ### Notes - If the dependency graph contains a cycle (tasks cannot be completed), specify what you would return (e.g., `-1`) and implement accordingly. ### Example If `n = 3` and `deps = [[1,3],[2,3]]`, tasks 1 and 2 can run in parallel in time 1, then task 3 runs in time 2, so the answer is 2.