如何将 adjacency_list 类型的图复制到 adjacency_list 类型的另一个图?
typedef adjacency_list<setS, setS, undirectedS, NodeDataStruct, EdgeDataStruct> MyGraph;
MyGraph g1, g2;
// processing g1: adding vertices and edges ...
// processing g2: adding some vertices and edges ...
g1.clear();
g1 = g2 // this gives an execution error (exception)
g1 = MyGraph(g2); // this also gives an execution error
g2.clear();