JAVA: Complete the following method removeLeaves() RECURSIVELY USING ONE HELPER FUNCTION.

public class MyIntSET {

private Node root;

private static class Node {

public final int key;

public Node left, right;

public Node(int key) { this.key = key; }

}

// tree is semi-perfect if every node is semi-perfect

// A node with 0 children is semi-perfect.

// A node with 1 child is NOT semi-perfect.

// A node with 2 children is semi-perfect if (size-of-larger-sized-child <= size-of-smaller-sized-child * 3)

// Here, larger and smaller have to do with the SIZE of the children, not the key values.

// hint: in the helper, return -1 if the tree is not semi-perfect, otherwise return the size

public boolean isSemiBalanced() {

//

//

// add a child with key=0 to all nodes that have only one child

// (you do not need to retain symmetric order or uniqueness of keys, obviously)

public void addZeroToSingles() {