441. Arranging Coins #

Problem Statement #

You have n coins and you want to build a staircase with these coins. The staircase consists of k rows where the ith row has exactly i coins. The last row of the staircase may be incomplete.

Given the integer n, return the number of complete rows of the staircase you will build.

Example 1:

Input: n = 5
Output: 2
Explanation: Because the 3rd row is incomplete, we return 2.

Example 2:

Input: n = 8
Output: 3
Explanation: Because the 4th row is incomplete, we return 3.

Constraints:

• 1 <= n <= 231 - 1

Solution: #

impl Solution {
    pub fn arrange_coins(n: i32) -> i32 {
        let (mut n, mut i) = (n, 1);

        while n >= i {
            n -= i;
            i += 1;
        }

        i - 1
    }
}

... #