run the algorithm to find the path list

def solve(m,c):
    """
    run the algorithm to find the path list
    """
    G={ (m,c,1):[] }
    frontier=[ (m,c,1) ]  # 1 as boat starts on left bank 
    while len(frontier) > 0:
        hold=list(frontier)
        for node in hold:
            newnode=[]
            frontier.remove(node)
            newnode.extend(pick_next_boat_trip(node, m,c, frontier))
            for neighbor in newnode:
                if neighbor not in G:
                    G[node].append(neighbor)
                    G[neighbor]=[node]
                    frontier.append(neighbor)
    return mod_plan.find_path_BFS(G,(m,c,1),(0,0,0))