1716. Calculate Money in Leetcode Bank

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.

class Solution {
public:
    int totalMoney(int n) {
        int q = n / 7, r = n % 7;
        return 28 * q + q * (q - 1) / 2 * 7 + q * r + r * (r + 1) / 2;
    }
};