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Lesson 8. Dictionary

Difficulty level:

иконка человека красный иконка человека белая иконка человека зеленая Pythonlib

Task«Flight time»

💻 Python
The airline provided data on the time of direct flights between different cities. You need to find the minimum flight time between two specified cities, given the possible transplants. Each transplant requires an additional 1 hour. RN
Direct flights are presented in the form of couples "city-city" and the time of flight in the flight in the time hours. If there is no direct flight between the cities, you need to find the optimal route through other cities.

Input format

The first line contains the number of direct flights N. The following n lines contain information about flights in the format "City1 City2 Time". The last line contains cities of departure and destination through a gap

Output format

the minimum time of the flight in the clock or "the route is not found" if it is impossible to get

Example

Input

5
Moscow St. Petersburg 2
Kazan Kazan 3
Moscow Yekaterinburg 4
Yekaterinburg Kazan 2
Kazan Novosibirsk 3
Moscow Novosibirsk

Output

8

Hint

There will be no clue here, decide for yourself!

main.py
Test 1
Test 2
Test 3
Test 4
Test 5
Test 6
Test 7
Test 8
Test 9
Test 10
Developer’s solution

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How to Solve Tasks?

1 - Read the task and understand what needs to be done

2 - The example shows how the input data will be provided and what output is expected

3 - Write the code considering the input, output, and the task itself.

(see example below)
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Difference Between the "Run" and "Test on All Cases" Buttons

1 - The “Run” button executes your code only on one set of input data, and you’ll see the result in the output window.

2 - The “Test on All Cases” button runs your code against all test cases. If all tests pass, a banner will appear. If even one test fails, it will be highlighted in red.

(see example below)
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How to Change Input Data

To change the input data, click the “Run Test” button next to the input data you want to execute.

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Working with Input/Output Windows

1 - Input Data is the window containing the values loaded into your program in place of input()

2 - Program Output is the window showing what your program prints. If it’s green, the output matches the expected result; if red, there are differences.

3 - Expected Output is the reference value used to verify the solution.

(see example below)
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Guide to the "Run Test" Button

1 - Green means the program produced the correct output

2 - Red means the program’s output didn’t match the expected output for this data. The program output and the expected output must be identical, including spaces and punctuation!

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Criteria for a Correct Solution — How to Know It’s Right

If you see this banner, congratulations — everything is correct.

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Topic Structure (30 Tasks: 10 Easy, 10 Medium, 10 Hard)

1 - The first 10 tasks are quite easy and contain hints covering only the essential parts of the topic.

2 - The next 10 tasks are medium difficulty. Their hints differ from the easy ones and reveal new aspects of the topic.

3 - The hardest tasks have no hints. Often, they include additional topics, so sometimes it’s better to move on and return later. Read the hints carefully — they offer new ways to solve already familiar problems.

(see example below)
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Availability of Theory (Video + Text)

1 - Each block contains a “Theory” section.

2 - It always includes a detailed video.

3 - There is also a detailed guide with all the necessary theory and code examples.

(see example below)
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Social Media Links for Feedback

1 - Click the “Report an Error / Social Media” button

2 - Here you can describe the error you encountered.

3 - You’ll also find our social media links here — follow us and help us improve.

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🎉 Congratulations! 🎉

You did an excellent job with the task! It was a challenging problem, but you found the correct solution. You are one step closer to mastering programming! Keep up the good work, because every stage you pass makes you even stronger.

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