NOIP2016 to improve the group preliminary (C + + language) test questions personal random analysis

Recently in the previous round of the preliminary question, then I picked up a few more representative questions to say it well

The original question can be seen here: Https://wenku.baidu.com/view/10c0eb7ce53a580217fcfede.html?from=search

The following is purely personal analysis of the random, not to see (wrong

Individual selection

T2. A mouse in the keyboard Caps LOCK key, a key, S key, the D key jumps to jump, ask the screen on the output of the 81st character.

Obviously there is a periodicity, asdsaasdsa for a cycle, you can learn t=10, so the 81st character is 81 10 = 1, that is, the first character A.

T6. Suffix expressions

Know an infix expression A * (B+c)-D, to replace it with a suffix expression, this has a lot of methods, I use the method may be more troublesome, but not easy to make mistakes

First we have the formula A * (B+C)-D,

Add parentheses in order of operation, which will be ((A * (B+C))-D),

In each parenthesis, put the operator behind the operand,

((A (bc+) *) D-)

By deleting all brackets, there is abc+*d-, that is, the final answer.

One thing to note is that adding parentheses refers to adding parentheses once for each operation so that if there are multiple calculations in parentheses, parentheses are also required.

For example, A * (b+c*e)-D, the result of parentheses should be ((A * (b + (c*e))-D), you must ensure that each parenthesis can only be one operation.

When moving a symbol, the suffix expression is required to put all the symbols before the appropriate closing parenthesis, so that the prefix expression is the same, put in the corresponding opening parenthesis after the good.

T9. If the address bus has n bits, the computer will use up to 2n bytes of data, the problem is 32-bit address line, this should be 232 bytes of data, converted to GB, only need to divide by 1024 three times.

T12.

(Lucia don't you know that the friends Circle has the ability to set access permissions?) ）

You may not believe it, this is a graph topic. First, there is a graph, from a point, it can go to any of the location of the Unicom, reached the point, and then to its connection in all directions of each side, so that a walk can reach many points. Now given this starting point, choose some direction, but no matter where you go, it can't go to a specific point.

Take four options and bring them all in one place to see which line is not.

T13.

This problem is actually the CPU's pipeline processing method. We assume that three courses are a,b,c, three processes are recorded as two-way, and we know that at the same time each person can only do one process, and the process must be in order, but not the same.

That's good. First 10 minutes, do A1, next 10 minutes do A2 and B1, then next 10 minutes do a3,b2,c1 ...

Just like this:

T14. What kind of main theorem do you want to use? Never heard of ...

Take the time to learn to learn well.

Non-directed selection

T3. Quick sort and Merge sort all have one step to divide the operation of the interval, the thought of dividing and treating is embodied here.

T5. Don't forget to take your clothes. 233333

Not to be continued

NOIP2016 to improve the group preliminary (C + + language) test questions personal random analysis