class Solution {
public:
int bitSquareSum(int n) {
int sum = 0, bit;
while(n > 0)
{
bit = n % 10;
sum += bit * bit;
n = n / 10;
}
return sum;
}
bool isHappy(int n) {
int slow = n, fast = n;
do
{
slow = bitSquareSum(slow);
fast = bitSquareSum(fast);
fast = bitSquareSum(fast);
}
while(slow != fast);
return slow == 1;
}
};