算法-哈希表-快乐数

class Solution {
    
    
    public boolean isHappy(int n) {
    
    
        Set<Integer> set = new HashSet<>();

        while(n != 1 && !set.contains(n)) {
    
    
            set.add(n);
            n = getNext(n);
        }

        return n == 1;
    }

    public int getNext(int n) {
    
    

        int ans = 0;
        while(n != 0) {
    
    
            int d = n % 10;
            n = n / 10;
            ans += d * d;
        }

        return ans;
    }
}