Is the Build Order Feasible?

medium

A monorepo has n packages, numbered 0 to n - 1. Each rule [a, b] in deps means package a depends on package b — b must be built before a.

Return True if there exists some order that builds all n packages, or False if the dependency rules make it impossible (i.e. they contain a cycle).

Example 1

in n = 2, deps = [[1, 0]]

out True

Build 0, then 1.

Example 2

in n = 2, deps = [[1, 0], [0, 1]]

out False

Each package waits on the other — deadlock.

Constraints

· 1 <= n <= 100
· 0 <= len(deps) <= 500
· deps[i] = [a, b] with 0 <= a, b < n