public void borrowElement(BTreeNode self, BTreeNode parent, int pos,
			BTreeNode brother) {
		state = State.borrow;
		self.numOfElements += 1;

		self.value[self.numOfElements] = parent.value[pos]; // parentposԪ½
		parent.value[pos] = brother.value[1]; // ֵܽڵСԪpos
		// Ԫ
		for (int i = 2; i <= brother.numOfElements; i++) {
			brother.value[i - 1] = brother.value[i];
		}
		if (!brother.isLeaf) { // ƶ
			self.children[self.numOfElements] = brother.children[0]; // ƶֵܽڵСԪص
			// ƶʣຢ
			for (int i = 1; i <= brother.numOfElements; i++) {
				brother.children[i - 1] = brother.children[i];
			}
		}

		brother.numOfElements -= 1;

	}