LintCode: Happy Number

C++

 class Solution {
 public:
     /**
      * @param n an integer
      * @return true if this is a happy number or false
      */
     bool isHappy(int n) {
         // Write your code here
         int a, b;
         if (n <= ) return false;
         if (n < ) n = n*n;
         while (n > ) {
             a = ;
             while (n) {
                 b = n%;
                 a += b*b;
                 n /= ;
             }
             n = a;
         }
         return n == ;
     }
 };