由于博主太菜，题目集还不完整，有待更新。
判断题
1.m阶B树的根结点最多有m棵子树。
T
F
2.In a B+ tree, leaves and nonleaf nodes have some key values in common.
T
F
3.A 2-3 tree with 12 leaves may have at most 10 nonleaf nodes.
T
F
选择题
1.下列叙述中，不符合m阶B树定义要求的是：
B.根结点最多有m棵子树
C.所有叶结点都在同一层上
D.各结点内关键字均升序或降序排列
2.Among the following statements, which one does NOT satisfy the definition of a B tree of order m?
B.The root has at most m subtrees
C.All the leaf nodes are on the same level
D.Inside each node, the keys are arranged in sorted order
3.B+树不同于B树的特点之一是：
B.结点中含有关键字
C.根结点至少有两个分支
D.所有叶结点都在同一层上
4.After deleting 9 from the 2-3 tree given in the figure, which one of the following statements is FALSE?
B.the second key stored in the root is 6
C.6 and 8 are in the same node
D.6 and 5 are in the same node
5.Which of the following statements concerning a B+ tree of order M is TRUE?
B.not all leaves are at the same depth
C.leaves and nonleaf nodes have some key values in common
D.all nonleaf nodes have between ⌈M/2⌉ and M children
6.下列关于M阶B+树的说法，哪一句是对的？
B.不是所有的叶结点都有同样的深度
C.叶结点和非叶结点中存的有一些键值是一样的
D.所有非叶结点都有⌈M/2⌉到M个孩子
10.Which one of the following is NOT true about B+ trees and AVL trees: they are both __。
B.fit for sequential searches
C.fit for random searches
D.fit for range searches
13.高度为 5 的 3 阶 B 树含有的关键字个数至少是：
B.31
C.62
D.242
14.The minimum number of keys in a B tree with order 3 and height 5 is __.
B.31
C.62
D.242
15.After inserting 0 into the 2-3 tree given in the figure, how many of the following statements are FALSE?
- (S1) The tree grows higher;
- (S2) 2 and 4 are in the same interior node;
- (S3) the root node still contains 9 only;
- (S4) the interior node containing 12 keeps unchanged.
B.1
C.2
D.3
16.在图中给定的 2-3 树中插入 0，以下描述有几句是错误的？
- (S1) 树变高了；
- (S2) 2 和 4 在同一个内部结点里；
- (S3) 根结点仍然只包含 9；
- (S4) 包含 12 的那个内部结点没有改变。
B.1
C.2
D.3
17.下面关于B-和B+树的叙述中，不正确的是（ ）。
B.B-树和B+树都可用于文件的索引结构
C.B-树和B+树都能有效地支持顺序检索
D.B-树和B+树都能有效地支持随机检索
18.m阶B-树是一棵（ ）。
B.m叉平衡排序树
C.m-1叉平衡排序树
D.m+1叉平衡排序树
19.To sort N records by merge sort, the worst-case time complexity is:
B.O(N)
C.O(NlogN)
D.O(N2)
20.To sort N records by merge sort, the space complexity is:
B.O(N)
C.O(NlogN)
D.O(N2)