Write an algorithm to determine if a number 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, and 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 numbers.

Example:

** Input**: 19

** Output**: true

Explanation:

1^2 + 9^2 = 82

8^2 + 2^2 = 68

6^2 + 8^2 = 100

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

Solution:

```
func isHappy(n int) bool {
visited := map[int]bool{}
for visited[n] != true && n != 1 {
visited[n] = true
t := 0;
for n != 0 {
t += (n%10) * (n%10)
n = n / 10
}
n = t
}
return n == 1
}
```