《快乐数》之做完了你就快樂了么？
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
private Set<Integer> set=new HashSet();
private int getNext(int n){
   int sum=0;
   while(n!=0){
      int cur=n%10;
      n=n/10;
      sum+=cur*cur;
   }
   return sum;
}

public boolean isHappy(int n) {
   while(n!=1){
      if(set.contains(n)){
          return false;
      }else{
          set.add(n);
      }
      n=getNext(n);
   }
   return n==1;
}