Introduction

In this blog post, we will explore how to solve the LeetCode problem "2240" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

You are given an integer total indicating the amount of money you have. You are also given two integers cost1 and cost2 indicating the price of a pen and pencil respectively. You can spend part or all of your money to buy multiple quantities (or none) of each kind of writing utensil. Return the number of distinct ways you can buy some number of pens and pencils. Example 1: Input: total = 20, cost1 = 10, cost2 = 5 Output: 9 Explanation: The price of a pen is 10 and the price of a pencil is 5. - If you buy 0 pens, you can buy 0, 1, 2, 3, or 4 pencils. - If you buy 1 pen, you can buy 0, 1, or 2 pencils. - If you buy 2 pens, you cannot buy any pencils. The total number of ways to buy pens and pencils is 5 + 3 + 1 = 9. Example 2: Input: total = 5, cost1 = 10, cost2 = 10 Output: 1 Explanation: The price of both pens and pencils are 10, which cost more than total, so you cannot buy any writing utensils. Therefore, there is only 1 way: buy 0 pens and 0 pencils. Constraints: 1 <= total, cost1, cost2 <= 106

Explanation

Here's an efficient solution to the problem, along with an explanation:

• Iterate through possible pen quantities: The outer loop iterates through the number of pens that can be bought, from 0 up to the maximum possible number without exceeding the total cost.
• Calculate remaining money: For each pen quantity, calculate the remaining money that can be spent on pencils.

• Calculate possible pencil quantities: Divide the remaining money by the cost of a pencil and add 1 (to include the case of buying 0 pencils). Add this number to the total count of ways.

• Runtime Complexity: O(total/cost1), Storage Complexity: O(1)

Code

    def waysToBuyPensPencils(total: int, cost1: int, cost2: int) -> int:
    """
    Calculates the number of distinct ways to buy pens and pencils.

    Args:
        total: The total amount of money.
        cost1: The cost of a pen.
        cost2: The cost of a pencil.

    Returns:
        The number of distinct ways to buy pens and pencils.
    """

    ways = 0
    for num_pens in range(total // cost1 + 1):
        remaining_money = total - num_pens * cost1
        ways += (remaining_money // cost2 + 1)
    return ways