int randomPartition(std::vector<int>& arr, int low, int high) {    
    int random = low + rand() % (high - low + 1);    
    std::swap(arr[random], arr[high]);    
    int pivot = arr[high];    
    int i = low - 1;    
    for (int j = low; j < high; j++) {        
        if (arr[j] <= pivot) {            
            i++;            
            std::swap(arr[i], arr[j]);        
        }    
    }    
    std::swap(arr[i + 1], arr[high]);    
    return i + 1;
}
void quickSort(std::vector<int>& arr, int low, int high) {    
    if (low < high) {        
        int pi = randomPartition(arr, low, high);        
        quickSort(arr, low, pi - 1);        
        quickSort(arr, pi + 1, high);    
    }
}