Edges
tree [ 1 ] . push_back ( 2 ) ; tree [ 2 ] . push_back ( 1 ) ; tree [ 1 ] . push_back ( 3 ) ; tree [ 3 ] . push_back ( 1 ) ; tree [ 2 ] . push_back ( 4 ) ; tree [ 4 ] . push_back ( 2 ) ; tree [ 3 ] . push_back ( 5 ) ; tree [ 5 ] . push_back ( 3 ) ;