LeetCode 202. 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

class Solution {
public:

bool isHappy(int n) {
int num[10]={0,1,4,9,16,25,36,49,64,81};
vector<int> vect;
int sum=0;
vector<int>::iterator it;
while(sum!=1){
it=find(vect.begin(),vect.end(),n);
if (it!=vect.end()){
return false;
}
else{
vect.push_back(n);
}
sum=0;
while(n!=0){
int c=n%10;
n=n/10;
sum+=num[c];
}
n=sum;
}
return true;
}
};