Question
You are given a directed graph with n nodes (0..n-1) and edges [u, v]. You may travel along an edge in its given direction for free, or traverse it against its direction by paying 1 (reversing that edge). Return the minimum number of edge reversals needed to get from src to dst, or -1 if dst is unreachable even with reversals. Assume 1 <= n <= 100000; a 0-1 BFS in O(V+E) is the intended solution.
min_edge_reversals(n: int, edges: list[list[int]], src: int, dst: int) → int[4,[[0,1],[1,2],[3,2]],0,3]out1State 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.