Analysis of task 3 of the USE 2017 in computer science from the demo project. This is a basic level task. Estimated time to complete the task is 3 minutes.
Content elements to be tested: ability to represent and read data in different types information models (diagrams, maps, tables, graphs and formulas).
Task 3:
In the figure on the right, the road map of the N-sky district is shown as a graph; the table on the left contains information about the length of each of these roads (in kilometers).
Since the table and the 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 point B to point C. In your answer, write down an integer - as it is indicated in the table.
Answer: ________
Line P5 must correspond to the vertex from which 4 arcs emerge.
Such a peak is IN
P5 - V
Line P6 must correspond to the vertex from which 2 arcs emerge.
Such a peak is A
P6 - A
Roads from point A lead to point B and point C.
It is obvious that from point A to point C the length is 7 km, therefore to point B - 5 km.
So line P1 corresponds to the vertex B.
P1 - B
The task is to determine the length of the road from point B to point C.
According to the table, we determine that the path from B V IN equals 8 .
For effective training in computer science for each task, a brief theoretical material is given to complete the task. More than 10 training tasks with analysis and answers were selected, developed on the basis of the demo version of previous years.
There are no changes in KIM USE 2019 in informatics and ICT.
The areas in which the knowledge test will be carried out:
- Programming;
- Algorithmization;
- ICT tools;
- Information activity;
- Information processes.
Necessary actions when preparing:
- Repetition of the theoretical course;
- Solution tests in informatics online;
- Knowledge of programming languages;
- Pull up mathematics and mathematical logic;
- Use a wider range of literature - the school curriculum for success in the exam is not enough.
Exam Structure
The duration of the exam is 3 hours 55 minutes (255 minutes), of which one and a half hours are recommended to be devoted to completing the tasks of the first part of the KIMs.
Tasks in tickets are divided into blocks:
- Part 1- 23 tasks with a short answer.
- Part 2- 4 tasks with a detailed answer.
Of the proposed 23 tasks of the first part of the examination paper, 12 belong to the basic level of knowledge testing, 10 - to increased complexity, 1 - to a high level of complexity. Three tasks of the second part high level complexity, one - increased.
When solving, it is obligatory to record a detailed answer (arbitrary form).
In some tasks, the text of the condition is submitted immediately in five programming languages - for the convenience of students.
Points for tasks in computer science
1 point - for 1-23 tasks
2 points - 25.
3 points - 24, 26.
4 points - 27.
Total: 35 points.
To enter a technical university of an intermediate level, you must score at least 62 points. To enter the metropolitan university, the number of points must correspond to 85-95.
To successfully write an examination paper, you need a clear command of theory and constant practice in solving tasks.
Your formula for success
Work + work on mistakes + carefully read the question from beginning to end to avoid mistakes = maximum score on the exam in computer science.
Computer science. USE
Task 3
Analysis of typical tasks:
Determine the length of the shortest path between points A and F, provided that you can only move along the roads indicated in the table.
The problem is solved by converting the tabular model into a tree:
R 
Consider the first row (column) of the table. Obviously, from point A we can get to points B, C,D
,
F
. We get the following diagram:
R 
Let's look at the second row (column) of the table: from point B you can get to point A (the path AB has already been plotted on the diagram and there is no need to redraw it, because this is the “back” road and such a route will not be the shortest). Thus, it is necessary to plot one road on the diagram (from B toD
, length 5).
Analyzing the 3rd row (column) of the table, we add one more road to the diagram: from C toD length 2.
Analysis of 4 rows (columns) of the table adds two more roads to our scheme (fromD VE AndF ), since the roadsBD , CD , AD are already on the chart. Since the pointD on the diagram is drawn 3 times, then from each pointD Let's take two paths:DE AndD.F. . Get the schema
According to the 5th line (column) of the table, we will put a road on the diagramEF :
According to the scheme, we write out routes from A toF and calculate their length:
AF-14
ADF - 7+8=15
ADEF – 7+5+1=13
ACDF – 4+2 +8 =14
ACDEF - 4+2+5+1 = 12
ABDF - 3+5+8 = 16
ABDEF - 3+5+5+1 = 14
The shortest path is 12.
Roads were 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 the points.
How many such routes are there from A to F that pass through five or more settlements? Points A and F should be taken into account when calculating. You cannot go through the same point twice.
We build a tree diagram similarly to No. 1. The difference from the previous task lies in the fact that we are not interested in the length of the routes and we will put on the diagram all the points that can be reached from this point that were not previously marked by us on this branch:
Four routes (indicated in blue on the diagram) turned out to be a dead end, so further movement along them leads to a revisit of points A orD . We write out routes leading to the pointF (marked in red in the diagram) and count the number settlements through which each route passes:
AF- 2
ADF- 3
ADEF- 4
ACDF-4
ACDEF- 5
ABDF- 4
ABDEF - 5
The number of routes that meet the condition of the problem is 2.
The table shows the cost of transportation between neighboring railway stations. Specify the schema corresponding to the table.
4) 
Analyzing the table by rows (by columns), we get: 4 roads should be present on the diagram: AB (4), AD (5), BC (3), BD (6). Of the four circuits, only one circuit (the last one) satisfies this condition. Answer: 4 scheme.
In the figure on the right, the road map of the N-sky district is shown as a graph; the table contains information about the lengths of these roads (in kilometers).
Since the table and the 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 point B to point E. In your answer, write down an integer - as it is indicated in the table.
The task is to establish a correspondence between the numbering of settlements on the graph and in the table.
Let's analyze the graph: according to the scheme, it leads to points A, B, E and K along 2 paths, to point D - 3 paths, C - 5 paths, E - 4 paths. Comparing with the table, we get: G is P2 in the table, V is P6, E is P4. Let's replace the row and column headings in the table with the corresponding letters:
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