Introduction

In this blog post, we will explore how to solve the LeetCode problem "1716" 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

Hercy wants to save money for his first car. He puts money in the Leetcode bank every day. He starts by putting in $1 on Monday, the first day. Every day from Tuesday to Sunday, he will put in $1 more than the day before. On every subsequent Monday, he will put in $1 more than the previous Monday. Given n, return the total amount of money he will have in the Leetcode bank at the end of the nth day. Example 1: Input: n = 4 Output: 10 Explanation: After the 4th day, the total is 1 + 2 + 3 + 4 = 10. Example 2: Input: n = 10 Output: 37 Explanation: After the 10th day, the total is (1 + 2 + 3 + 4 + 5 + 6 + 7) + (2 + 3 + 4) = 37. Notice that on the 2nd Monday, Hercy only puts in $2. Example 3: Input: n = 20 Output: 96 Explanation: After the 20th day, the total is (1 + 2 + 3 + 4 + 5 + 6 + 7) + (2 + 3 + 4 + 5 + 6 + 7 + 8) + (3 + 4 + 5 + 6 + 7 + 8) = 96. Constraints: 1 <= n <= 1000

Explanation

Here's the solution:

• Calculate the number of full weeks and remaining days.
• Calculate the sum of money saved in full weeks using arithmetic series.

• Calculate the sum of money saved in the remaining days.

• Runtime Complexity: O(1), Storage Complexity: O(1)

Code

    def totalMoney(n: int) -> int:
    weeks = n // 7
    days = n % 7

    total = 0

    # Calculate money for full weeks
    if weeks > 0:
        total += weeks * 28 + 7 * (weeks * (weeks - 1)) // 2

    # Calculate money for remaining days
    start_day_value = weeks + 1
    total += (days * (2 * start_day_value + days - 1)) // 2

    return total