README_EN.md

comments	difficulty	edit_url	rating	source	tags
true	Easy	https://github.com/doocs/leetcode/edit/main/solution/1700-1799/1716.Calculate%20Money%20in%20Leetcode%20Bank/README_EN.md	1294	Biweekly Contest 43 Q1	Math

1716. Calculate Money in Leetcode Bank

中文文档

Description

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

Solutions

Solution 1

Python3

class Solution:
    def totalMoney(self, n: int) -> int:
        a, b = divmod(n, 7)
        return (28 + 28 + 7 * (a - 1)) * a // 2 + (a * 2 + b + 1) * b // 2

Java

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

C++

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

Go

func totalMoney(n int) int {
	a, b := n/7, n%7
	return (28+28+7*(a-1))*a/2 + (a*2+b+1)*b/2
}