[LeetCode][python3]Day02. Happy Number (30-Day LeetCoding Challenge)

30 days! Lets go Lets go!
N2I -2020.04.02

1. My solution

class Solution:
    def isHappy(self, n: int) -> bool:
        return self.check(n)
        
    def check(self,n):
        if n==1 or n==7:
            return True
        elif len(str(n))==1:
            return False
        s=0
        for i in str(n):
           s+=int(i)**2
        return self.check(int(s))

Explanation:

Remember to use return self.check(s) instead of self.check(s), or else you will get a return None in the answer.