Cycle length in functional graph
You are given a functional graph as an array next where next[i] is the single outgoing edge from node i (every node has exactly one successor), or -1 if node i has no successor (a terminal). Starting from node 0 and repeatedly following next, return the length of the cycle you eventually enter, or 0 if the walk terminates (reaches a -1) without ever entering a cycle. Indices in next are valid node indices or -1.
Implement
cycle_length_from_zero(next_arr: list[int]) → intExamples
in
[[1,2,3,1]]out3What 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.
0:00 of about 30 min
solution.py
InputExpectedGot
[[1,2,3,1]]3not run yetsample