题目
You have a total of n coins that you want to form in a staircase shape, where every k-th row must have exactly k coins.
Given n, find the total number of full staircase rows that can be formed.
n is a non-negative integer and fits within the range of a 32-bit signed integer.
解题思路
1 + 2 + ... + k <= N
先转换成等式
k = (-1+sqrt(1+8*n))/2
最后的答案是k的取整
代码
class Solution:
def arrangeCoins(self, n: int) -> int:
return int((-1 + math.sqrt(1 + 8 * n)) / 2)
