Difference(int[] a){
        this.elements = a;
    }
    
    void computeDifference(){        
        for(int i=0; i<elements.length-1; i++){
            for(int j=i+1; j<elements.length; j++){
                int diff = Math.abs(elements[i]-elements[j]);
                if(diff > maximumDifference){
                    this.maximumDifference = diff;             
                }
            }
        }
    }