# https://leetcode-cn.com/problems/qiu-12n-lcof
class Solution:
def __init__(self):
self.res = 0
def sumNums(self, n: int) -> int:
n > 1 and self.sumNums(n - 1)
self.res += n
return self.res
s = Solution()
s.sumNums(3)
s = Solution()
s.sumNums(9)
class Solution:
def __init__(self):
self.res = 0
def sumNums(self, n: int) -> int:
n > 1 and self.sumNums(n - 1)
self.res += n
return self.res
6 << 1
6 >> 1