public static void getDecisionTree(Node N,int n){
		if(N!=null){
			if(getGini(N.getDocList())==0||N.getDocList().size()<=n){
				N.setLeftChild(null);
				N.setRightChild(null);
			    N.setClassify(nodeClassify(N));
			}
			else{
				Node left=new Node();
				Node right=new Node();
				Attribute_selection_method(N,left,right);
				if(left.getDocList().size()==0||right.getDocList().size()==0){
					N.setLeftChild(null);
					N.setRightChild(null);
					N.setClassify(nodeClassify(N));
				}
				else{
					N.setLeftChild(left);
					N.setRightChild(right);
					getDecisionTree(left,n);
					getDecisionTree(right,n);
					
				}
			}
		}
	}