Python Solution for Codeforces Problem 546A - Soldier and Bananas

Introduction

Codeforces 546A, also known as "Soldier and Bananas," brings us into a delightful scenario involving a soldier, bananas, and a simple yet interesting mathematical problem. In this article, we will explore the problem and dive into the provided Python code to decipher how the soldier manages to satisfy his craving for bananas.

The Soldier's Bananas Dilemma

Imagine a soldier with a love for bananas. He decides to buy 'w' bananas from a street vendor, and each banana costs 'k' dollars. However, being a soldier on a tight budget, he decides to sell some of his old belongings to fund his banana feast. The soldier sells enough items to have 'n' dollars in his pocket.

The challenge is to determine how much money the soldier will have left after buying 'w' bananas.

Understanding the Code

Let's break down the Python code provided and see how it tackles the soldier's banana-buying adventure.

k, n, w = map(int, input().split())
s = 0

for i in range(1, w+1):
    s += k*i
    
s -= n
if s < 0:
    print(0)
else:
    print(s)

1. Input Reading:

   - The first line of code takes user input using `input()`. The `map(int, input().split())` part is used to split the input into three integers: 'k' (cost per banana), 'n' (initial amount the soldier has), and 'w' (number of bananas to buy).

2. Calculation with Loop:

   - The code then initializes a variable 's' to 0, which will represent the total cost of the bananas.

   - It uses a `for` loop to iterate from 1 to 'w+1', calculating the cumulative cost of each banana purchase and adding it to 's'.

3. Adjustment for Money Spent:

   - After the loop, the code subtracts the initial amount 'n' from 's'. This step represents the soldier's spending on bananas.

4. Conditional Check:

   - The code checks if the remaining amount 's' is negative. If so, it means the soldier didn't have enough money to buy all the bananas.

5. Print Result:

   - If the remaining amount is negative, it prints 0 (indicating the soldier can't afford any bananas).

   - Otherwise, it prints the remaining amount of money.

Example Illustration

Let's consider an example:

- If 'k' is 2 (cost per banana), 'n' is 20 (initial amount), and 'w' is 4 (number of bananas), the soldier spends 2 + 4 + 6 + 8 = 20 dollars.

- After subtracting the initial amount, 's' becomes 20 - 20 = 0, indicating the soldier has no money left.

Conclusion

Codeforces 546A provides a playful yet mathematically interesting challenge, simulating a soldier's banana-buying adventure. The code efficiently calculates the total cost of bananas and determines the soldier's remaining funds. This problem showcases the combination of loop iteration and conditional checks to solve a real-world-inspired problem in a programming context.