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Question
A directed graph is given as an adjacency list: graph[i] is the list of nodes reachable in one step from node i. A node is 'safe' if every walk starting from it eventually reaches a terminal node (a node with no outgoing edges) without ever entering a cycle. Return the sorted list of all safe nodes. Terminal nodes are trivially safe.
Implement
safe_nodes(graph: list[list[int]]) → list[int]Examples
in
[[[1,2],[2,3],[5],[0],[5],[],[]]]out[2,4,5,6]What a strong answer looks like
State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.
Learn the concepts
Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.
Run or narrate your approach, then ask the coach.