Test book for Unified State Examination computer science. Demo options

The lesson is devoted to how to solve task 3 of the Unified State Exam in computer science

The 3rd topic is characterized as tasks of a basic level of complexity, completion time - approximately 3 minutes, maximum score - 1

* Some page images are taken from the presentation materials of K. Polyakov

Information structuring and information models

Let us briefly consider the necessary solutions 3 Unified State Exam assignments concepts.

Structuring information- this is the establishment of the main elements in information messages and the establishment of connections between them.

Structuring is done with purpose facilitating the perception and retrieval of information.

Structuring is possible using the following structures (information models):

listing of elements collected according to a characteristic feature;

Vasya, Petya, Kolya 1, 17, 22, 55

In a set, ordering of elements is not necessary, i.e. The order is not important.

The order of the elements is important.

The tables highlight objects(individual table records) and properties(column names or row names):

Let's consider family relationships in the tree:

Root– node without ancestors (A).
Sheet– a node without children (D, E, F, G).
Height– the greatest distance from the root to the leaf (number of levels).

Let's say there are the following folders (directories) with files on your computer's hard drive:

We get a tree:

Sometimes it is very difficult to structure information using the structures described because of the complex “relationships” between objects. Then you can use graphs:

is a set of vertices and connections between them, called edges:

Graph showing roads between villages

is a graph that has a path between any of its vertices.

Tree is a connected graph without cycles

Weighted graphs have an “edge weight”:

A weight matrix is ​​obtained from weighted graphs, and the inverse transformation is also possible.

Finding the shortest path (brute force)

Definition shortest path between points A and D

• In USE tasks on this topic, two information models are most often used - tables and diagrams.
• Information in the table is constructed according to the following rules: at the intersection of a row and a column there is information that characterizes the combination of this row and column.
• On the diagram information is based on next rule: if there is a connection between the objects of the diagram, then it is displayed by a line connecting the names of these objects on the diagram.

Solving tasks 3 of the Unified State Exam in computer science

Unified State Examination in Informatics 2017, assignment from the collection of Ushakova D.M., option 1:

In the figure, the road map of the N district is shown in the form of a graph; the table contains information about the lengths of these roads (in kilometers).

Since the table and diagram were drawn independently of each other, the numbering of settlements in the table has nothing to do with letter designations on the graph.
Determine how long the road from point is D to point TO. In your answer, write down the integer as it is indicated in the table.

• Consider the graph and count the number of edges from each vertex:

Result: 20

In addition, you can watch a video of the solution to this Unified State Exam assignment in computer science:

3 task. Demo version of the Unified State Exam 2018 computer science (FIPI):

In the figure, the road map of the N-sky district is shown in the form of a graph; the table contains information about the length of each of these roads (in kilometers).

Since the table and diagram were drawn independently of each other, the numbering of settlements in the table is in no way connected with the letter designations on the graph. Determine the length of the road from the point A to point G. In your answer, write down the integer as it is indicated in the table.

• Let's count how many edges each vertex has:

Result: 6

For a detailed solution to this 3rd task from the demo version of the Unified State Exam 2018, watch the video:

Solution 3 of the Unified State Examination task in computer science (control version No. 1 exam paper 2018, S.S. Krylov, D.M. Ushakov):

Between settlements A, B, C, D, E, F roads have been built, the length of which is shown in the table (if the cell is empty, there is no road).

Determine the length of the shortest path between points A And F .

Result: 11

Video analysis of the task:

Solution 3 of the Unified State Examination in computer science (11th version of the State Examination in computer science 2018):

Roads have been built between settlements A, B, C, D, E, F, the length of which is shown in the table. The absence of a number in the table means that there is no direct road between points.

Determine the length shortest path between points A And F provided that you can only travel on the roads indicated in the table.

Result: 12

Solution 2* of the Unified State Examination in Informatics 2018, option 10 (FIPI, “Unified State Examination Informatics and ICT, standard exam options 2018”, S.S. Krylov, T.E. Churkina):

Between settlements A, B, C, D, E, F, Z One-way roads have been built. The table shows the length of each road (the absence of a number in the table means that there is no direct road between points).

How many such routes are there from A V Z, which pass through five or more settlements? Items A And Z take into account when calculating. You cannot go through the same checkpoint twice.

* in the new textbooks, tasks 2 and 3 have been swapped: now 2 is Finding the shortest path, and 3 is Algebra of Logic

Result: 6

Analysis of task 3 of the Unified State Exam option No. 1, 2019 Computer science and ICT Standard exam options (10 options), S.S. Krylov, T.E. Churkina:

The figure shows a road map of the N-rayon; in the table, an asterisk indicates the presence of a road from one settlement to another; the absence of an asterisk means that there is no such road. Each settlement on the diagram corresponds to its number in the table, but it is not known which number.

1 2 3 4 5 6 7 8 1 * * * 2 * * * 3 * * 4 * * * * * * 5 * * * 6 * * * 7 * * * 8 * * *

Determine which numbers of settlements in the table can correspond settlements D And E on the diagram? In your answer, write down these two numbers in ascending order without spaces or punctuation.

• First, let's find unique vertices - those that have a unique number of edges: this A(2 ribs) and H(6 ribs). In the table they correspond to numbers 3 and 4:

	1	2	A	H	5	6	7	8
1			*	*			*
2			*	*				*
A	*	*
H	*	*			*	*	*	*
5				*		*	*
6				*	*			*
7	*			*	*
8		*		*		*

• According to the diagram, we find that the adjacent vertices for A are B And G. In the table we determine the numbers corresponding to them - 1 and 2. Since according to the assignment they do not interest us, we designate them together:

	B,G	B,G	A	H	5	6	7	8
B,G			*	*			*
B,G			*	*				*
A	*	*
H	*	*			*	*	*	*
5				*		*	*
6				*	*			*
7	*			*	*
8		*		*		*

• Both vertices B and G are adjacent to the already known A and H and, in addition, the vertices F And C. From the first column or first row we find that F or C will correspond to the number 7, and from the second line to the number 8. Let us designate them in the table:

	B,G	B,G	A	H	5	6	F,C	F,C
B,G			*	*			*
B,G			*	*				*
A	*	*
H	*	*			*	*	*	*
5				*		*	*
6				*	*			*
F,C	*			*	*
F,C		*		*		*

• As a result, we obtain that the required vertices are D And E- numbers correspond 5 And 6 . Since it does not matter which digit this or that vertex should correspond to, in the answer we will simply write these digits in ascending order.

Online Unified State Exam test in computer science looks most organic. But in reality, it's not that simple. Programming is not the most simple ability to assess skills. The programmer may not remember some operators, but knows where to find the necessary information and how to apply it correctly. Therefore, the Unified State Exam in computer science does not completely objectively assess the skills of schoolchildren, as experts note. This picture is observed in many subjects: C students receive high scores, and good students fail their favorite subject. Many people have a question: why is this happening?

How to get high scores on the Unified State Exam?

The answer is simple - it's all about preparing for the exam. It is enough to spend some time preparing for the exam, and not studying the subject, and you can greatly improve your result. The main difficulty of the Unified State Exam is that students do not understand the questions. Sometimes all the answers seem to fit or all the answers don't fit if you look critically at their wording. Every person thinks differently, especially question writers and school graduates. The student needs to understand the algorithm Unified State Examination work and learn to solve typical tasks. Preparatory courses, if good, will help you prepare for the Unified State Exam in the shortest possible time. Universities have teaching materials, according to which they teach visitors to preparatory courses to pass the Unified State Exam. In addition, after such courses, there will be an opportunity to preferential terms.

Online Unified State Exam tests on the website website

But you can’t rely entirely on outside training. In addition, not everyone has the means to pay for such courses. So you need to practice self-training. However, reading textbooks may not be enough. You need to get used to the test method of assessing knowledge and understand the algorithm for solving questions from the upcoming exam. Online is best for this. Unified State Exam tests in computer science. We have on our website online tests By various subjects. All of them are freely available, for preparation in computer science, you can use the online Unified State Exam tests in computer science an unlimited number of times, and you will not have a limited time. In addition, the site does not require registration and sending SMS to access this convenient tool self-preparation such as online Unified State Examination tests in computer science.

For school graduates. It should be taken by those who plan to enter universities in the most promising specialties, such as Information Security, automation and control, nanotechnology, system analysis and control, missile systems and astronautics, nuclear physics and technology and many others.

Check out general information about the exam and start preparing. There are practically no changes compared to last year in the new version of the KIM Unified State Exam 2019. The only thing is that fragments of programs written in the C language disappeared from the tasks: they were replaced with fragments written in the C++ language. And from task No. 25, they removed the opportunity to write an algorithm in natural language as an answer.

Unified State Exam assessment

Last year, to pass the Unified State Exam in computer science with at least a C, it was enough to score 42 primary points. They were given, for example, for correctly completing the first 9 tasks of the test.

It is not yet known exactly what will happen in 2019: we need to wait for the official order from Rosobrnadzor on the correspondence of the primary and test scores. Most likely it will appear in December. Considering that the maximum primary score for the entire test remains the same, most likely the minimum score will not change either. Let's focus on these tables for now:

Structure of the Unified State Exam test

Computer science is the longest exam (the Unified State Examination in mathematics and literature is the same length), lasting 4 hours.

In 2019, the test consists of two parts, including 27 tasks.

• Part 1: 23 tasks (1–23) with a short answer, which is a number, a sequence of letters or numbers.
• Part 2: 4 tasks (24–27) with detailed answers, complete solutions to the tasks are written down on answer sheet 2.

All tasks are connected in one way or another with a computer, but during the exam you are not allowed to use it to write a program in group C problems. In addition, the tasks do not require complex mathematical calculations You are also not allowed to use a calculator.

Preparation for the Unified State Exam

• Take the Unified State Exam tests online for free without registration or SMS. The tests presented are identical in complexity and structure to the actual exams conducted in the corresponding years.

• Download demo versions of the Unified State Examination in computer science, which will allow you to better prepare for the exam and pass it easier. All proposed tests have been developed and approved for preparation for the Unified State Exam. Federal Institute pedagogical measurements (FIPI). All official versions of the Unified State Exam are developed in the same FIPI.
  The tasks that you will see most likely will not appear on the exam, but there will be tasks similar to the demo ones, on the same topic or simply with different numbers.

General Unified State Examination figures

WITH modern world technologies and realities of programming, development Unified State Exam in Computer Science has little in common. There are some basic points, but even if you understand a little about the tasks, this does not mean that you will ultimately become a good developer. But there are a great many areas where IT specialists are needed. You can't go wrong if you want to have Fixed salary above average. In IT you will get it. Provided, of course, that you have the appropriate abilities. And you can develop and grow here as much as you want, because the market is so huge that you can’t even imagine! Moreover, it is not limited only to our state. Work for any company from anywhere in the world! This is all very inspiring, so let preparation for the Unified State Exam in computer science be the first minor step, followed by years of self-development and improvement in this area.

Structure

Part 1 contains 23 short answer questions. This part contains short-answer tasks that require you to independently formulate a sequence of symbols. The assignments test the material of all thematic blocks. 12 tasks relate to basic level, 10 tasks for an increased level of complexity, 1 task for a high level of complexity.

Part 2 contains 4 tasks, the first of which higher level difficulty, the remaining 3 tasks high level difficulties. The tasks in this part involve writing a detailed answer in free form.

3 hours 55 minutes (235 minutes) are allotted to complete the examination work. It is recommended to spend 1.5 hours (90 minutes) to complete the tasks of Part 1. It is recommended to devote the rest of the time to completing the tasks of part 2.

Explanations for grading assignments

Completion of each task in Part 1 is worth 1 point. Part 1 task is considered completed if the examinee gives an answer that corresponds to the correct answer code. Completion of tasks in part 2 is graded from 0 to 4 points. Answers to tasks in Part 2 are checked and assessed by experts. Maximum amount The points you can get for completing tasks in part 2 are 12.

Two players, Pasha and Valya, are playing next game. There is a pile of stones in front of the players. The players take turns, Pasha makes the first move. In one move a player can add one stone to the pile or double the number of stones in the pile. For example, having a pile of 15 stones, in one move you can get a pile of 16 or 30 stones. Each player has something to do
moves, there is an unlimited number of stones.
The game ends when the number of stones in the pile becomes at least 20. If at the same time it turned out in the heap no more than 30 stones, then the winner is the player who made the last move. Otherwise, his opponent becomes the winner. For example, if there were 17 stones in the pile and Pasha doubles the number of stones in the pile, then the game will end,
and Valya will be the winner. IN starting moment there were S stones in the pile, 1 ≤ S ≤ 19.
We will say that a player has a winning strategy if he can win with any moves of the opponent. To describe a player's strategy means to describe what move he should make in any situation that he may encounter. different game enemy.

Complete the following tasks.
1. a) For what values ​​of the number S can Pasha win in one move? List all such values ​​and Pasha's corresponding moves.
b) Which player has winning strategy at S = 18, 17, 16? Describe winning strategies for these cases.
2. Which player has a winning strategy when S = 9, 8? Describe relevant winning strategies.
3. Which player has a winning strategy when S = 7? Construct a tree of all games possible with this winning strategy (in the form of a picture or table). On the edges of the tree indicate who is making the move; in nodes - the number of stones in a position.

Do not enter anything in the answer field. The correct answer can be checked by clicking the "Parsing" button

1. a) Pasha can win if S = 19 or S = 10, 11, 12, 13, 14, 15. With S = 19, the first move is to add one stone to the pile; for the remaining specified values ​​of S, you need to double the number of stones.
b) When S = 16, 17 or 18, doubling the number of stones does not make sense, since after such a move the opponent wins. Therefore, we can assume that the only possible move is to add one stone to the pile.
At S = 18, after such a move by Pasha, there will be 19 stones in the pile. In this position, the one who walks (i.e. Valya) wins (see point 1a):

with S = 18 Pasha (the player who must go first) loses. Valya has a winning strategy.
At S = 17, after Pasha adds one stone with his first move, there will be 18 stones in the pile. In this position, the mover (i.e. Valya) loses (see above): with S = 17, Pasha (the player who must move first) wins. Pasha has a winning strategy.
When S = 16, Valya has a winning strategy. Indeed, if Pasha doubles the number of stones on his first move, then the pile becomes 32 stones, and the game immediately ends with Vali winning. If Pasha adds one stone, then the pile becomes 17 stones. As we already know, in this position the player who must move (i.e. Valya) wins.
In all cases, winning is achieved by the fact that during his move, the player with a winning strategy must add one stone to the pile.

2. When S = 9 or 8, Pasha has a winning strategy. It consists of doubling the number of stones in the heap and getting a heap in which there will be 18 or 16 stones, respectively. In both cases, the player who makes the move (now it’s Valya) loses (section 1b).

3. When S = 7, Valya has a winning strategy. After Pasha's first move, the pile can have either 8 or 14 stones. In both of these positions, the player who makes the move (now Valya) wins. The case S = 8 is considered in section 2, the case S = 14 is considered in section 1a.