Alibaba campus R & D Engineer recruitment exam, Alibaba

Alibaba campus R & D Engineer recruitment exam, Alibaba

The original question is from the Network: http://www.cnblogs.com/nausicaa/p/3946694.html. I will answer questions based on my understanding. Due to the limited level of knowledge, there are some things I will not do or do wrong. You are welcome to leave a message for discussion. This blog will be updated continuously. Thank you for your attention!

1. 2/5 of a team can write Java programs, 3/4 can write C ++ programs, and at least () people in this team can write Java and C ++ at the same time.
A. 3 B. 4 C. 5 D. 8 E. 15 F. 20

2. A team leader receives an emergency project and wants to consider some of the six team members, codenamed ABCDEF, to participate in project development. Candidates must meet the following requirements:
At least one of the two AB members participates.
AD cannot all go
AEF should include two members
Both of them go or do not go
One member of CD
If D does not participate, E does not participate.
Then () participate in emergency project development.
A. ecef B. AF C. ECF D. F E. ABCF F. ECDEF

3. the opposing parties compete for a commodity worth 1. The strategies that can be adopted by both parties can be divided into the pigeon strategy and the e strategy. If both parties adopt a pigeon strategy, each party has a 1/2 chance of obtaining the item. If both parties adopt an e strategy, each party has a 1/2 probability of winning. The winner has a value of 1, the cost of the value is 1, and the negative party pays the price of the value 1. If one is a pigeon strategy and the other is an e strategy, the e strategy obtains the item with the value 1. No one knows whether the opponent is a pigeon strategy or an e strategy before the competition results come out. When the proportion of the person who chooses the pigeon strategy is a certain value, the expected benefits of the pigeon strategy and the e strategy are the same. The value is:

A. 0.2 B. 0.4 C. 0.5 D. 0.7 E. 0.8 F. None of the above

4. In a small-end machine, if

union X{    int x;    char y[4];};

If:

X;

A. x = 0x11223344; // hexadecimal

Then:

A. a. y [0] = 11

B. a. y [1] = 11

C. a. y [2] = 11

D. a. y [3] = 11

E. a. y [0] = 22

F. a. y [3] = 22

5. Which of the following operations is faster for arrays than linear tables ()

A. Reverse Order

B. Insert a header

C. Return the intermediate node

D. Return to the header Node

E. select random nodes

6. In a Linux system, an executable file is root and has a setid. When a common user mike runs this program, the valid users of the generated process and the actual users are ()

A. root mike B. root C. mike root D. mike E. deamon mike F. mike deamon

7. There are four processes A, B, C, and D, so that they enter the ready queue in sequence. Because the difference is very short, it can be considered as arriving at the same time. The four processes run in 11, 7, 2, and 4 time units respectively by rotation, and set the time slice to 1. The average turnaround time of the four processes is ()

A. 15.25 B. 16.25 C. 16.75 D. 17.25 E. 17.75 F. 18.25

8. In a bidirectional cyclic linked list, the pointer p points to the node (not the end node) and inserts the node pointed to by the pointer s. The operation to modify the pointer is ()

A. p-> next = s; s-> prev = p; p-> next-> prev = s; s-> next = p-> next;

B. p-> next-> prev = s; p-> next = s; s-> prev = p; s-> next = p-> next;

C. p-> next-> prev = s; s-> prev = p; p-> next = s; s-> next = p-> next;

D. s-> prev = p; s-> next = p-> next; p-> next-> prev = s; p-> next = s;

E. s-> next = p-> next; s-> prev = p; p-> next = s; p-> next-> prev = s;

9. Among the following options, () is a typical TCP client (actively establishes a connection and closes the connection)

A. SYNC_SENT-> ESTABLISHED-> FIN_WAIT_1-> FIN_WAIT_2-> TIME_WAIT

B. SYNC_SENT-> ESTABLISHED-> FIN_WAIT_1-> FIN_WAIT_2-> CLOSE_WAIT

C. SYNC_SENT-> SYNC_RCVD-> ESTABLISHED-> FIN_WAIT1-> FIN_WAIT2

D. SYNC_RCVD-> ESTABLISHED-> CLOSE_WAIT-> TIME_WAIT-> LAST-> ACK

E. SYNC_RCVD-> ESTABLISHED-> CLOSE_WAIT-> TIME_WAIT-> FIN_WAIT1

F. SYNC_SEND-> ESTABLISHED-> FIN_WAIT1-> TIME_WAIT-> CLOSE_WAIT

10. We know that the result of the forward traversal of a binary tree is (ACDEFHGB), and the result of the forward traversal is (DECAHFBG). Could you tell me the result of the backward traversal is ()

A. HGFEDCBA

B. EDCHBGFA

C. BGFHEDCA

D. EDCBGHFA

E. BEGHDFCA

F. BGHFEDCA

11. A museum will enter at a rate of 20 people per minute. On average, each person will stay for 20 minutes. Ask the museum to accommodate at least () people.

A. 100 B. 200 C. 300 D. 400 E. 500

12. the number of 50 K series must be sorted from small to large, and the series features are basically in reverse order (most numbers are from large to small, and some numbers are out of order ), which of the following sorting algorithms can have the highest probability of optimal performance without having to know the characteristics of a series in advance (without considering space limitations )()

A. Bubble Sorting B. Improve Bubble Sorting C. Select sort D. Fast sort E. Heap Sort F. Insert sort

13. In the dynamic memory allocation (malloc in C language, new in C ++), the resulting storage area is in the memory ()

A. Static Zone B. heap C. stack D. stack E. kernel memory F. uncertain

14. The "Village Chief" took 4 pairs of fathers and sons to the shooting of a village in the third quarter of "Where is Dad. There is a millennial rule in the village to protect children from being abducted, that is, when they eat, they can only be other children or their own parents. Then there are several ways for the four fathers and sons to sit on the round table. (After rotating, the direction of each person is changed, it is a new method )()

A. 144 B .240 C. 288 d.20.e. 576 F. 960

15. Each physical computer can Virtualize 20 virtual machines. Assume that a virtual machine fails only when the physical machine it hosts fails. 100 virtual machines are virtualized from five physical machines. Which of the following statements about the failure of these 100 virtual machines are true ()

A. the failure rate of A single virtual machine is higher than that of A single physical machine

B. The failure of these 100 VMS is independent of each other.

C. The number of failures of the 100 virtual machines per unit time is higher than the number of failures of the 100 physical machines per unit time

D. Unable to determine which of the 100 virtual machines and 100 physical machines are more reliable

E. If five virtual machines are randomly selected to form a cluster, the reliability of the cluster is the same as that of the five physical machines.

F. Only one virtual machine may fail for a period of time.

16. Which of the following C code does not belong to undefined behaviors ()

A. int I = 0; I = (I ++ );

B. char * p = "hello"; p [1] = 'E ';

C. char * p = "hello"; char ch = * p ++;

D. int I = 0; printf ("% d \ n", I ++, I -);

E. All behaviors are undefined.

F. None of them are undefined behaviors.

17. The condition for determining that the head of the single-chain table of the lead node is null is ()

A. head = null

B. head-> next = null;

C. head-> next = head;

D. head! = Null;

E. * head = null;

F. * (head-> next) = null;

18. When the departure interval between the first and second routes is 10 minutes, the departure time of the bus is 1 and 9 respectively. The probability of a random arrival of a passenger is

A. 0.1 B .0.2 C. 0.3 D. 0.4 E. 0.5 F. 0.9

19. 20. All forgot

Short answer

1. Given a query and a text, both consist of lower-case letters. It is required to find the length of the longest continuous letter sequence in the query in the same order. For example, if the query is "acbac" and the text is "acaccbabb", the "CBA" in the text is the longest continuous character sequence that appears in the query. Therefore, the returned result must be 3 characters long. Pay attention to program efficiency.

2. Write a function and input a binary tree. each node in the tree stores an integer. The function returns the absolute value of the difference between the two nodes with the greatest difference in the tree. Pay attention to program efficiency.

3. What is the difference between the wait and sleep methods in Java.

Others:

21. There are a total of 2020 grids on the board, starting from 1. The first piece is placed in the 1st lattice, and the number of forward grids is determined by throwing a dice, and the x lattice is pushed forward when the x point is thrown. The dice have 6 sides, corresponding to 1 to 6 respectively. The quality is even. When the number of pawns reaches 2014 or exceeds 2014, the game ends. Then, the probability of a piece reaching 2014 is the closest.
A.m. 2/3
B. 1/2
C. 1/3
D. 2/7.
E. 1/6
F. 1/7

22. There are two 32bit numbers A and B. Use the following method to obtain the 32bit numbers C and D. Which one can use C and D to obtain the values of A and B?

A. C = (int32) (A + B), D = (int32) (A-B)

B. C = (int32) (A + B), D = (int32) (A-B)> 1)

C. C = (int32) (A + B), D = B

D. C = (int32) (A + B), D = (int32) (A + 2 * B)

E. C = (int32) (A * B), D = (int32) (A/B)

23. Which of the following methods cannot be used for program optimization?

A. improve data access methods to improve cache hit rate

B. Improve the efficiency of I/O-intensive operations by using multiple threads

C. Use the database connection pool to replace direct database access

D. Use iteration instead of Recursion

E. Merge multiple remote calls for Batch Sending

F. Shared redundant data improves access efficiency

24. Use 6 blocks of 1X2 ceramic tiles and fill the ground with 2x6 tiles. Which of the following different paving methods are available? (tiles cannot be divided into small blocks)

A.13

B .15

C.22

D.24

E.25

F.26