LeetCode：Happy Number

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Happy Number——LeetCode
Write an algorithm to determine if a number is “happy”.

A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process ends in 1 are happy numbers.

Example: 19 is a happy number

1^2 + 9^2 = 82
8^2 + 2^2 = 68
6^2 + 8^2 = 100
1^2 + 0^2 + 0^2 = 1

就是按照题目一边一边循环来求出是不是和为1,如果不是1的话，总会是那些个数来回出现，用一个set去装一下sum，来判断一下就可以

public class Solution {    public boolean isHappy(int n) {        Set<Integer> set=new HashSet<Integer>();        int sum=n;        while(sum!=1){            n=sum;            sum=0;            while(n!=0){                int tmp=n%10;                sum+=tmp*tmp;                n=n/10;            }            if(set.contains(sum)){                return false;            }            set.add(sum);        }        return true;    }}

代码大部分人都是一样的，只不过我在百度的时候发现，有的博客不光代码一样，连说的话都一样。
一如既往的开头：这道题是Leetcode上面的题，很简单balabala···
真是不装会死

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