Question
You are given an n x n matrix `rates` where `rates[i][j]` is the exchange rate from currency i to currency j (rates[i][i] = 1). An arbitrage opportunity exists if you can start with one unit of some currency, perform a sequence of conversions, and end up with strictly more than one unit of the same currency. Return true if any arbitrage cycle exists, false otherwise. Assume 2 <= n <= 60 and all rates are positive.
has_arbitrage(rates: list[list[float]]) → bool[[[1,2],[0.4,1]]]outfalseState 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.