Cheapest Flights Within K Stops

def findCheapestPrice(n, flights, src, dst, k):
    prices = [float("inf")] * n
    prices[src] = 0
    
    for i in range(k + 1):
        tmpPrices = prices.copy()
        
        for s, d, p in flights:
            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]