cpp-flashcards/org/study_deck_02/dsa/math-geometry/0202-happy-number.org

#+ANKI_DECK: study_deck_02
* TODO 0202. Happy Number :easy:
:PROPERTIES:
:NEETCODE: [[file:../../roadmap.org::*0202. Happy Number][0202. Happy Number]]
:END:

Write an algorithm to determine if a number ~n~ is happy.

A *happy number* is a number defined by the following process:

 - Starting with any positive integer, replace the number by the sum of the squares of its digits.

 - Repeat the process until the number equals 1 (where it will stay), or it *loops endlessly in a cycle* which does not include 1.

 - Those numbers for which this process *ends in 1* are happy.

Return ~true~ /if/ ~n~ /is a happy number, and/ ~false~ /if not/.

*Example 1:*


#+begin_src
Input: n = 19
Output: true
Explanation:
12 + 92 = 82
82 + 22 = 68
62 + 82 = 100
12 + 02 + 02 = 1
#+end_src


*Example 2:*


#+begin_src
Input: n = 2
Output: false
#+end_src


*Constraints:*

 - ~1 <= n <= 2^{31} - 1~

** TODO Approach
Write your approach here.

** TODO Python
#+begin_src python :lc-problem 202 :lc-lang python3
class Solution:
    def isHappy(self, n: int) -> bool:
#+end_src

** TODO C++
#+begin_src cpp :lc-problem 202
class Solution {
public:
    bool isHappy(int n) {
        
    }
};
#+end_src