roblem 3: Create a program named TreeweightedSum.java and implement the following method: public int weightedSum (BT bt) This method accepts a BT as a parameter and returns the sum of the values stored in a binary tree of integers weighted by the depth of each value. You should return the value at the root plus 2 times the values stored at the next level of the tree plus 3 times the values stored at the next level of the tree plus 4 times the values stored at the next level of the tree and so on. For example, in the tree below: 10 4. 20 6 25 The sum would be computed as: 1 * 9 2 * (5 + 10) + 3 * (4 7 20) + 4 * (6 + 25)256