leetcode-Happy Number

Question:

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

Solution:

class Solution {    public:    bool isHappy(int n) {        if(n == 0){            return false;        }        n = getNum(n);        unordered_set<int> mset;        while(mset.insert(n).second){            if(n == 1){                return true;            }            n = getNum(n);        }        return false;    }    int getNum(int n){        int res = 0;        while(n){            int tmp = n % 10;            res += tmp * tmp;            n /= 10;        }        return res;    }};

总结：

unordered_set的函数insert返回值中各个版本都不一致：

(1)
pair