* @param index
	 * @param num
	 */
	private void buildBySum(K[] kArray, int index, int value) {
		if(index >= (kArray.length-1))
			return;
		
		if(kArray[index]==null)
			throw new NullPointerException("key value can not be null!");
		
		//Search for the tempHST in children list
		SumTree<K> tempSumTree = new SumTree<K>(kArray[index]);		
		int indexOfChildren = children.indexOf(tempSumTree);
				
		if(indexOfChildren >= 0){
			tempSumTree = children.get(indexOfChildren);
			tempSumTree.incrSum(value);
			tempSumTree.buildBySum(kArray, ++index, value);
		}else{
			tempSumTree.incrSum(value);
			tempSumTree.buildBySum(kArray, ++index, value);
			children.add(tempSumTree);
		}
	}