vector<int> closestNumbers(vector<int> arr) {
    sort(arr.begin(), arr.end());
    vector<int> pairs;
    int lowest = INT16_MAX;
    
    for(int i=0; i<arr.size(); i++){
        
        if((i+1)<arr.size()){
            int diff = arr[i+1]-arr[i];
            
            if(diff==lowest){
                pairs.push_back(arr[i]);
                pairs.push_back(arr[i+1]);
            }
            
            if (diff<lowest) {
                lowest = diff;
                pairs.clear();
                pairs.push_back(arr[i]);
                pairs.push_back(arr[i+1]);
            }
        }
    }
    
    return pairs;
}