边工作边刷题:70天一遍leetcode: day 38-1
happy number
错误点
- loop中什么时候加入set?check之后update:loop invariantcheck,加入setupdate。所以一定要在loop中首先加入set
class Solution(object):
def isHappy(self, n):
"""
:type n: int
:rtype: bool
"""
uset = set()
while n not in uset:
uset.add(n)
ss = 0
while n>0:
ss+=(n%10)*(n%10)
n/=10
if ss==1: return True
n=ss
return False