leetcode-202-Happy Number

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

直接模拟。

class Solution {
public:
    bool isHappy(int n) {
        if (n == 1) return true;
        int m ;
        map<int,int>a;
        while (n != 1) {
            if (a[n] == 1) break;
            a[n] = 1;
            m = 0 ;
            while (n) { 
                m += (n%10) * (n%10) ;
                n = n/10 ;
            }
            n = m ;
            if (n == 1) return true;
        }
        return false;
    }
};

leetcode-202-Happy Number

class Solution { public: bool isHappy(int n) { if (n == 1) return true; int m ; map<int,int>a; while (n != 1) { if (a[n] == 1) break; a[n] = 1; m = 0 ; while (n) { m += (n%10) * (n%10) ; n = n/10 ; } n = m ; if (n == 1) return true; } return false; } };