data structure and algorithms

Task 1 Create a Java application to construct an expression (binary) tree from the postfix expression using Stacks. Note: Construct trees using stacks. For this task, create a binary tree using doubly linked list. Doubly linked list class should be created from scratch and for stack class, you can use JCF Stack class. Write a program to demonstrate. Task 2 Write a Java program for array-based implementation of a heap. Create following basic methods: createHeap() // Creates an empty heap. heapIsEmpty() // Determines whether a heap is empty. heapInsert(newItem) // Inserts newItem into a heap. heapDelete() // Retrieves and then deletes a heap’s root item. Write a program to demonstrate these methods.