#202

Happy Number

easy· Math & Geometryruns: 0

Write an algorithm to determine if a number n is happy. A happy number is defined as follows: starting with any positive integer, replace the number by the sum of the squares of its digits and repeat. The number is happy if it eventually reaches 1; otherwise it loops endlessly in a cycle that does not include 1. Return true if n is happy, otherwise false.

wpm 0acc 100%time 0:000 / 211

class Solution:
    def isHappy(self, n: int) -> bool:
        seen = set()
        while n != 1 and n not in seen:
            seen.add(n)
            n = sum(int(d) ** 2 for d in str(n))
        return n == 1

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