Java! Работа с trees.

Написать решения для 4ех заданий..

1. Write the expression tree constructor which takes an algebraic expression (infix but non-fully parenthesized expression) with no space, resets the root of the expression tree to such tree which constructed from the expression. The root set to null of the expression contains characters other than value, operator, and parenthesis or if it’s not a legal expression. You may assume each value is single digit only. public ExpressionTree(String expression){

2. Write a print method of ExpressionTree class which print the expression in fully parenthesized infix. If this method calls any other method, you have to implement such method. public void print();

3. Write levelOrder method of Tree class method which starts at the root of a tree and prints all elements of the tree in level-order (in one line). public void levelOrder();

4. Write a Tree class method which takes another tree, and check whether the parameter tree is a subtree of current tree. public boolean isSubTree(Tree);