leetcode/double_pointer/is_happy.py

import math
def isHappy(n: int) -> bool:
    if n == 1:
        return True
    while n != 1:
        n = str(n)
        a = 0
        for i in n:
            i = int(i)
            a = i * i + a
        if a < 10 and a > 1 and a != 7:
            return False
        n = a
    return True

print(isHappy(2))