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: 19 is a happy number
12 + 92 = 82
82 + 22 = 68
62 + 82 = 100
12 + 02 + 02 = 1
Solutions:
class Solution {
public:
bool isHappy(int n) {
if(n < 1) return false;
if( n == 1) return true;
set
occuredNums.insert(n);
while( 1 )
{
int count = 0;
while( n )
{
count += (n%10) * (n%10);
n /= 10;
}
if( count == 1) return true;
else if( occuredNums.find(count) != occuredNums.end() )
{
return false;
}
n = count;
occuredNums.insert( n );
}
}
};
