python coding test course, I will become the president of the women's association

I Will Become the Resident Association President – Python Coding Test Course

In this article, we will cover a famous problem called “I Will Become the Resident Association President” through an algorithm problem-solving course using Python.
This problem requires a solution using dynamic programming based on the given conditions.
We will define the problem, demonstrate the method through examples, and finally write the code to solve the problem.

Problem Description

Problem:
The resident association president is a resident living in apartment number B on the A-th floor, among N residents.
The apartment has K floors, and each floor has apartments numbered from 1 to K.
The problem is to calculate the total number of residents living in apartment B on the A-th floor.
The number of residents living in apartment B on the A-th floor varies depending on the apartment number on each floor, and the rule is as follows:

The number of residents in apartment B on the A-th floor = The number of residents in apartment 1 on the A-th floor + The number of residents in apartment 2 on the A-th floor + … + The number of residents in apartment B on the A-th floor
The number of residents in apartment B on the 1st floor is B.

For example, if we want to know the number of residents in apartment 4 on the 3rd floor, we need to add the number of residents from apartment 1 to apartment 4 on the 3rd floor.
The problem is to find the number of residents in apartment B on the A-th floor for the given A and B.

Input and Output Format

Input:
The first line contains the number of test cases T.
Following this, A and B will be given for each test case over T lines.

Output:
For each test case, print the number of residents in apartment B on the A-th floor.

Example

Input Example:
2
1 3
2 3

Output Example:
3
6

Problem-Solving Approach

To solve this problem, we can use a dynamic programming approach.
We can create a two-dimensional table to store the number of residents for each apartment number on each floor to solve the problem.

Step 1: Table Initialization

The number of residents on the 1st floor is always the same for each apartment number, so we initialize the table based on this.

Step 2: Set Dynamic Programming Relation

The number of residents in apartment B on each floor can be expressed as the sum of the number of residents from all apartments on the previous floor.
Therefore, the recurrence relation is as follows:

    dp[A][B] = dp[A-1][1] + dp[A-1][2] + ... + dp[A-1][B]

Step 3: Repetitive Process

Using the above recurrence relation, we calculate the values for A-th floor and apartment B through a loop.
This way, we will eventually obtain the number of residents in apartment B on the A-th floor.

Code Solution


def calculate_people(A, B):
    # Function to calculate the number of residents in apartment B on the A-th floor
    dp = [[0] * (B + 1) for _ in range(A + 1)]
    
    # Initialize the 1st floor
    for j in range(1, B + 1):
        dp[1][j] = j
    
    # Calculate number of residents using dynamic programming
    for i in range(2, A + 1): # A-th floor
        for j in range(1, B + 1): # B-th apartment
            dp[i][j] = sum(dp[i-1][k] for k in range(1, j + 1))
    
    return dp[A][B]

# Processing test cases
T = int(input())
for _ in range(T):
    A, B = map(int, input().split())
    print(calculate_people(A, B))

Conclusion

Through this problem, we explored the application of dynamic programming. We could understand how important it is to analyze the problem and design an algorithm to solve the given problem.
This approach can also help in finding more efficient solutions when solving other coding test problems.

More practice is needed to solve problems effectively. I hope you can develop an algorithmic mindset by solving a variety of problems.

Wishing you a successful coding test!

python coding test course, I will become the president of the women’s association