void decode_huff(node * root, string s) {
    
    node* curr=root;
    for(int i=0;i<s.length();i++)
    {
        if(s[i]=='0')
            curr=curr->left;
        else
            curr=curr->right;
    
        if(curr->left==NULL && curr->right==NULL)
        {
            cout<<curr->data;
            curr=root;
        }
    }
}