@@ -0,0 +1,510 @@
+public class Solution %7B%0A    public boolean isHappy(int n) %7B%0A        Set%3CInteger%3E set = new HashSet%3CInteger%3E();%0A        while (n != 1) %7B%0A            set.add(n);%0A            n = next(n);%0A            if (set.contains(n)) %7B%0A                return false;%0A            %7D%0A        %7D%0A        return true;%0A    %7D%0A    %0A    public static int next(int n) %7B%0A        int res = 0;%0A        %0A        while (n != 0) %7B%0A            int t = n %25 10;%0A            res += t * t;%0A            n /= 10;%0A        %7D%0A        return res;%0A    %7D%0A%7D%0A

Create HappyNumber_001.java