Cheapest Flights Within K Stops

class Solution:    def findCheapestPrice(self, n: int, flights: List[List[int]], src: int, dst: int, k: int) -> int:        prices = [float("inf")] * n        prices[src] = 0        for i in range(k + 1):            tmpPrices = prices.copy()            for s, d, p in flights:  # s=source, d=dest, p=price                if prices[s] == float("inf"):                    continue                if prices[s] + p < tmpPrices[d]:                    tmpPrices[d] = prices[s] + p            prices = tmpPrices        return -1 if prices[dst] == float("inf") else prices[dst]