# Leetcode - Happy Number Solution

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:**

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

**Example 2:**

```
Input: n = 2
Output: false
```

**Constraints:**

`1 <= n <= 2`

^{31}- 1

## Solution in python

```
class Solution:
def isHappy(self, n: int) -> bool:
def digitSum(n):
return sum(map(lambda x:x*x, map(int,list(str(n)))))
seen = set()
while not n in seen:
seen.add(n)
n = digitSum(n)
if n == 1:
return True
return False
```