C.{11,01,001,0101,0001}                                                 D.{0,10,110,1011}

7.如题7图所示二叉树的中序序列为

A．ACDB

B．DCBA

C．CDBA

D．ABCD

题7图

8．有向图中所有顶点入度之和与所有顶点出度之和的比是

A．1/2                                                                                 B.1

C．2                                                                                    D.4

9．含有n个顶点和e条边的有向图的邻接矩阵中，零元素的个数是

A.e                                                                                        B.2e

C.n²-2e                                                                                 D.n²-e

10.n个顶点的无向连通图，其生成树的边数为

A.n-l                                                                                     B.n

C.n+l                                                                                    D.nlogn

11．用自底向上的冒泡排序方法对序列(8,13,26,55,29,44)从大到小排序，第一趟排序需进行交换的次数为

A．2                                                                                    B.3

C．4                                                                                    D.5

12．对序列(8,13,26,55,29,44)从小到大进行基数排序，第一趟排序的结果是

A.(13,44,55,26,8,29)