Lexicographically smallest Eulerian circuit
Given a directed multigraph on n nodes (0..n-1) with a list of directed edges, reconstruct the lexicographically smallest Eulerian circuit: a closed walk starting and ending at the same node that uses every edge exactly once. Return it as the list of visited nodes (length = number_of_edges + 1). If no Eulerian circuit exists (degree imbalance or the edges are not all connected into one circuit), return an empty list. Start the circuit from the smallest-numbered node that has an outgoing edge. Constraints: 1 <= n <= 1000; edges may include self-loops and parallel edges.
lex_eulerian_circuit(n: int, edges: list[list[int]]) → list[int][3,[[0,1],[1,2],[2,0]]]out[0,1,2,0]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.
[3,[[0,1],[1,2],[2,0]]][0,1,2,0]not run yetsample