CF 329C(Graph Reconstruction-随机化求解-random_shuffle(a+1,a+1+n))
C.GraphReconstructiontimelimitpertest3secondsmemorylimitpertest256megabytesinputstandardinputoutputstandardoutputIhaveanundirectedgraphconsistingof n nodes,numbered1through n.Eachnodehasatmosttwoincid