LEETCODE-Happy Number

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
12 + 92 = 82
82 + 22 = 68
62 + 82 = 100
12 + 02 + 02 = 1

还没有看到哈希表，在这里用了一个偷懒的方法——用i去记录相加的次数，如果次数太多则认定为false；
等看完哈希表再来完善

class Solution {public:    bool isHappy(int n) {        int i = 0;    while (1) {        int sum = 0;        while (n != 0) {            int x = n % 10;            sum = sum + x * x;            n = n / 10;        }        n = sum;        if (n == 1)            return 1;        else            i++;        if (i == 25)            return 0;    }    }};