13.md

Form a number divisible by 3 using array digits

 int isPossible(int N, int arr[]) {
       
        long long sum=0;
        
        for(int i=0;i<N;i++)
        {
            int it=arr[i];
            while(it>0)
            {
                 sum +=it%10;
                 it=it/10;
            }
        }
           
        return sum%3==0;
    }