public class Solution { public boolean isHappy(int n) { Set<Integer> set = new HashSet<>(); while(n != 1 && !set.contains(n)){ set.add(n); int next = 0; do{ next += (n % 10) * (n % 10); }while((n /= 10) > 0); n = next; } return n == 1; } }
原文：http://www.cnblogs.com/puck/p/4609545.html