C++
1 class Solution { 2 public: 3 /** 4 * @param n an integer 5 * @return true if this is a happy number or false 6 */ 7 bool isHappy(int n) { 8 // Write your code here 9 int a, b; 10 if (n <= 0) return false; 11 if (n < 10) n = n*n; 12 while (n > 9) { 13 a = 0; 14 while (n) { 15 b = n%10; 16 a += b*b; 17 n /= 10; 18 } 19 n = a; 20 } 21 return n == 1; 22 } 23 };