[leet_code] 202. Happy Number with python3

문제 : https://leetcode.com/explore/featured/card/30-day-leetcoding-challenge/528/week-1/3284/ https://leetcode.com/problems/happy-number/

1. 4가 되면 무한루프가 나온다고 한다… ``` python

class Solution: def isHappy(self, n: int) -> bool: while n != 1: n = sum([int(i) ** 2 for i in str(n)]) if n == 4: return False

    return True ```

1. 풀이설명: 이미 나왔던 숫자가 다시 나오면 무한루프가 나오기 때문에 set을 이용해 무한루프 확인

   def isHappy(n: int) -> bool:
    notHappy = set()
    while n != 1:
        notHappy.add(n)
        n = sum([int(i) ** 2 for i in str(n)])
        if n in notHappy:
            return False
    return True