$/**$

$*$ See the spec on the website for tips and example behavior.

$*$

$*$ Also note: you may want to use private helper methods to help you solve these problems.

$*$ YOU MUST MAKE THE PRIVATE HELPER METHODS STATIC, or else your code will not compile.

$*$ This happens for reasons that aren't the focus of this assignment and are mostly skimmed over in

$*142$ and $143.$ If you want to know more, you can ask on the discussion board or at office hours.

$*$

$*$ REMEMBER THE FOLLOWING RESTRICTIONS:

$*-$ do not call any methods on the $`$IntTree$`$ objects

$*-$ do not construct new $`$IntTreeNode$`$ objects $($though you may have as many $`$IntTreeNode$`$ variables

$*$ as you like$).$

$*-$ do not construct any external data structures such as arrays, queues, lists, etc.

$*-$ do not mutate the $`$data$`$ field of any node; instead, change the tree only by modifying

$*$ links between nodes.

$*/$

public class IntTreeProblems $\{$

$/**$

$*$ Computes and returns the sum of the values multiplied by their depths in the given tree.

$*($The root node is treated as having depth $1.)$

$*/$

public static int depthSum$($IntTree tree$)\{$

$//$ TODO replace this with your code

throw new UnsupportedOperationException$("$Not implemented yet."$)$;

$\}$

$/**$

$*$ Removes all leaf nodes from the given tree.

$*/$

public static void removeLeaves$($IntTree tree$)\{$

$//$ TODO replace this with your code

throw new UnsupportedOperationException$("$Not implemented yet."$)$;

$\}$