Small knowledge, big challenge! This article is participating in the creation activity of “Essential Tips for Programmers”.

The four subjects of 408 do not talk about the most important data structure and algorithm, the other subjects such as OS process management and memory management, the TCP/IP model in the computer network, the representation of data in the computer group and so on, each of which is the content that a qualified programmer should focus on mastering.

So: although you may not go to graduate school, but follow the topic to deepen understanding of the always right

I will be updating 2 or 3 posts a day until I catch up (last time I was up to 10 posts a day). Please follow me or my column.

The exercises come from @Wangdao Weibo

The analysis is written by myself, if there are any questions or mistakes, please comment.

🎫 Data structure

Tree is best used to represent ___ (University of Chinese Academy of Sciences, 2012)

A. Ordered data elements B. Unordered data elements C. Data with branching hierarchical relationships among elements D. Unrelated data between elementsCopy the code

Answer and analysis

Answer: C

🔊 trees are non-linear data structures that are best suited for representing data with branching hierarchies, as can be seen from the shape of 😛

🎠 Computer network

Which of the following protocols uses TCP as its transport layer protocol ___ (Beijing University of Posts and Telecommunications 2011)

A. ICMP
B. IP
C. E-mail
D. SNMP
Copy the code

Answer and analysis

Answer: C

🔊 Common E-mail protocols include SMTP and POP3, both of which use TCP as the transport layer protocol. C.

Common protocols in the network are shown as follows:

🎡 Computer composition principle

If a program runs in a storage system consisting of L1 and L2Cache and main memory, the hit ratio of L1Cache and L2Cache is 50% and 80% respectively, the hit ratio of the entire storage system Cache is __ (Beijing University of Aeronautics and Astronautics, 2015)

A. 65%
B. 80%
C. 90%
D. 95%
Copy the code

Answer and analysis

Answer: C

🔊 The probability of both misses is:

C.

🎢 Operating system

The following is not correct ___ (University of Science and Technology Beijing 2014)

A. RAM can access information randomly b. When accessing RAM, the access time is independent of the physical location of the cell C. All information stored in memory is immutable. D. Ram and ROM can be addressed uniformlyCopy the code

Answer and analysis

Answer: C

🔊 Obviously, if the memory information cannot be changed, the cost of the computer will go through the roof!