7.14 - daily question - 408

One sentence per day ： May life be safe , cealess happiness
data structure ：

1. The following sequence is heap _______.（ Nanjing University of Aeronautics and Astronautics 2011 year ）
   A．{75,65,30,15,25,45,20,10}
   B．{75,65,45,10,30,25,20,15}
   C．{75,45,65,30,15,25,20,10}
   D．{75,45,65,10,25,30,20,15}

answer ：C
analysis ： First write each sequence as a complete binary tree , That is, the first element of the sequence is the root node of the complete binary tree , The second element of the sequence is the left child node of the root node , The third node of the sequence is the right child of the root node of the binary tree , In this way, a complete binary tree is formed according to this Law . Then, if each parent node of the binary tree is larger than its left and right child nodes , In this case , The sequence is the big top pile ; On the contrary, it is a small top pile .C Draw the sequence in the form of binary tree , For the big top pile , The remaining options do not match the heap definition .
expand ：
Pile up (Heap) It is a special data structure in computer science , yes The most efficient priority queue . A heap is usually a tree that can be seen as a tree Perfect binary tree Array object of .
The heap always satisfies the following properties ：

• The value of a node in the heap is always not greater than or less than the value of its parent node ;
• The heap is always a complete binary tree .
  

computer network
2. IP The packet must consider the maximum transmission unit MTU（Maximum Transfer Unit） To decide whether to slice the group , there MTU refer to ______ The largest transport unit of the layer .（ University of science and technology of China 2013 year ）
A． The network layer
B． Transport layer
C． The physical layer
D． The data link
answer ：D
analysis ：MTU Refer to IP The largest transmission unit of the data link layer below the layer , That's what's down here MAC Data field of frame , barring MAC The fields at the beginning and end of the frame . because IP Datagrams are loaded into MAC The data field in the frame , Therefore, the data link layer is very important MTU The number is IP Maximum length allowed for datagram ( It's the total length , That is, add a data field to the header ).

operating system
3．FAT File system , The external memory allocation method of the file system is ：_______. （ University of science and technology of China 2012 year ）
A. Continuous distribution
B. Implicit link assignment
C. Explicit link assignment
D. Index allocation
answer ：C
analysis ： Implicit link pointer on disk , Read the disk every time . A piece of memory used to display the chained structure of files on disk FAT Table to describe , When searching, you can locate it in memory and then read the disk . Much faster than implicit .
expand ：
Introduction to external memory allocation method ：https://blog.csdn.net/qq_63635872/article/details/123354817

The principle of computer organization
4. Add in complement / In the subtraction unit , Whether double sign bit or single sign bit is used , There has to be ______ circuit , It is usually realized by XOR gate .（ Nanjing University of Aeronautics and Astronautics 2015 year ）
A． decoding
B． code
C． Overflow judgment
D． displacement
answer ：C
analysis ： Memory type , Add in complement / In the subtraction unit , Whether double sign bit or single sign bit is used , There must be an overflow judgment circuit , It is usually realized by XOR gate .

All current topics are from @ The official account of King's Road online , The analysis of some topics is supplemented ,
If you have any questions or mistakes, please comment and let us know , Thank you for your support