# Leetcode 202 — Happy Number

## STOP stringifying numbers just to process the individual digits. Please, for the love of God.

In the last month I encountered multiple *algorithmic tasks* which involved the processing of individual digits in a number. And I found out a **very common** solution is to stringify the number and then process the letters as the separate digits. So I thought I’d share a better approach.

# Leetcode Example

This is the assignment of Leetcode 202 problem, also called Happy Number.

Write an algorithm to determine if a number

nis happy. Ahappy numberis 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 cyclewhich does not include 1.Those numbers for which this process

ends in 1are happy.

Now I found this solution on Youtube: Google LOVES this coding interview question. It’s in Python and it goes something like this:

`def isHappy(n: int) -> bool:`

seen = set()

current = str(n)

while current not in seen:

seen.add(current)

sum = 0

for digit in…