LeetCode 202. Happy Number

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