Code Room
CodingHardcod-g238
Subject Strongly connected componentsLevel Senior–Staff~40 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given a directed graph with n nodes (0..n-1) and edges [u, v], collapse each strongly connected component into a single super-node to form the condensation DAG. Return the number of source super-nodes (components whose in-degree in the condensation is zero). These are the minimum set of components you'd have to 'seed' to reach the whole graph. Constraints: 1 <= n <= 2000.

Implement
count_condensation_sources(n: int, edges: list[list[int]]) → int
Examples
in[5,[[0,1],[1,2],[2,0],[1,3],[3,4]]]out1
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.

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.