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.

Example 1: 

1
2
3
4
5
6
7
8
n = 5
The coins can form the following rows:
¤
¤ ¤
¤ ¤
Because the 3rd row is incomplete, we return 2.

Example 2: 

1
2
3
4
5
6
7
8
9
n = 8
The coins can form the following rows:
¤
¤ ¤
¤ ¤ ¤
¤ ¤
Because the 4th row is incomplete, we return 3.

思路

思路很简单，利用一个简单的while循环得到可以符合要求的行数。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
class Solution(object):
    def arrangeCoins(self, n):
        """
        :type n: int
        :rtype: int
        """
        if (n <= 0):
            return 0
        else:
            i = 0
            count = 0
            while (n > 0):
                i += 1
                count += 1
                if (n-i <= i):
                    break
                n -= i
                
            return count