there is an alternative way of implementing dijkstra's algorithm that avoids use of the locator pattern but increases the space used for the priority queue, , from to for a weighted graph, , with vertices and edges. the main idea of this approach is simply to insert a new key-value pair, , each time the value for a vertex, , changes, without ever removing the old key-value pair for . this approach still works, even with multiple copies of each vertex being stored in , since the first copy of a vertex that is removed from is the copy with the smallest key. describe the other changes that would be needed to the description of dijsktra's algorithm for this approach to work. also, what is the running time of dijkstra's algorithm in this approach if we implement the priority queue, , with a heap?