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Happy Number

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Problem statement

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 1 if n is a happy number, and 0 if not.

Function

isHappy(n: int) → int

Examples

Example 1

n = 19return = 1

1^2 + 9^2 = 82

8^2 + 2^2 = 68

6^2 + 8^2 = 100

1^2 + 0^2 + 0^2 = 1

Example 2

n = 2return = 0

The number 2 is not a happy number as it does not end in 1 after following the process.

Constraints

1 <= n <= 2^31 - 1