Description
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
Python3
class Solution:
def arrangeCoins(self, n: int) -> int:
return (int) (sqrt(1 + (8 * n)) - 1) // 2