A quick test of useful code.

Write a synchronous JavaScript function solve(input). Return only JavaScript, without Markdown or exports. Standard ECMAScript only: no filesystem, network, packages, Node globals, timers, or async. Inputs are valid under the contract. Return a JSON-serializable value. Do not mutate built-ins. Each case runs in a fresh QuickJS context with 16 MiB memory and a 100 ms CPU limit. All arithmetic inputs and results fit safe integers. We compare JSON structurally, ignoring object key order but preserving array order. Implement the full contract, not just an example.

Input: {jobs: {id: string, duration: nonnegative integer, deps: string[]}[], targets: string[]}. There are at most 240 jobs and 1000 dependency entries. IDs are unique strings of 1 to 24 ASCII letters, digits, or underscores. Every dependency and target names an existing job; repeated dependencies or targets have no extra effect. Ignore jobs not needed by a target, including any cycles in that ignored region. Required jobs are the targets and all their transitive dependencies. If the required graph has a cycle, return {error:"cycle"}. Otherwise return {order:string[], finish:integer, criticalPath:string[]}. order is the lexicographically smallest valid topological ordering of all required IDs: repeatedly take the smallest currently ready ID, not a whole batch. Jobs may execute with unlimited parallel workers; each starts as soon as all its dependencies finish. finish is the earliest time all targets are finished. criticalPath is a dependency chain starting at a dependency-free job and ending at any target with total duration equal to finish; choose the lexicographically smallest ID sequence among tied chains. Compare sequences element-by-element using ASCII order, with a proper prefix smaller than its extension. Empty targets returns {order:[],finish:0,criticalPath:[]}. Do not enumerate all paths: the case set includes a layered graph with exponentially many dependency paths. Times fit safe integers.