def Dijkstra(G,s):
    n = size(G)
    dist = []
    pred = []
    visited = []
    listaRistoranti = []


    for i in range(n):
        dist.append(inf)
        visited.append(False)
        pred.append(-1)
    dist[s] = 0


    for i in range(n-1):
        next = minVertex(dist,visited)
        visited[next] = True

        if kind(G,next) == "R":
            listaRistoranti.append(next)
        if len(listaRistoranti) == 3:
            return listaRistoranti

        V = neighbors(G,next)  #lista degli adiacenti di next

        for [z,w] in V:
            d = dist[next] + w
            if (dist[z] > d):
                dist[z] = d
                pred[z] = next

    return listaRistoranti




    def Dijkstra(G,s,destination,k):
        n = size(G)
        dist = []
        pred = []
        visited = []
        for i in range(n):
            dist.append(inf)
            visited.append(False)
            pred.append(-1)
        dist[s] = 0


        for i in range(n-1):
            next = minVertex(dist,visited)
            visited[next] = True
            if next == destination:
                if dist[next] <= k:
                    return True
                else:
                    return False

            V = neighbors(G,next)
            for [z,w] in V:
                d = dist[next] + w
                if (dist[z] > d):
                    dist[z] = d
                    pred[z] = next

        return False