Chapter 18, Problem 13PE

Program Plan Intro

Find the minimum in a Heap

Program plan:

Filename: “MinHeap.java”

This code snippet creates a class “MinHeap”. In the code,

• Import the required packages.
• Define a class “MinHeap”.
  • Create an array list “elements”.
  • Define the constructor “MinHeap()”.
    • Define the array list “elements”.
    • Initialize “elements” with “null”.
  • Define a method “add()”.
    • Add a new leaf using “add()”.
    • Declare a variable “index” and set the value to it.
    • Iterate a “while” loop,
      • Set elements to “elements” using method “set()”.
      • Get the parent index of “index”.
        • Set the “newElement” to “index” using “set()”.
  • Define a method “peak()” of type “E”.
    • Get the first element of “elements” and return the value.
  • Define a method “remove()”.
    • Get the first element of “elements” to “minimum”.
    • Define the “lastIndex”.
    • Get the element at “lastIndex” to “last”.
    • If “lastIndex” is greater than 1,
      • Add element “last” at index 1.
      • Call the method “fixHeap()”.
        • Return “minimum”.
  • Define a method “fixHeap()”,
    • Get the first element to “root”.
    • Define the variable “lastIndext” by setting last index of “elements”.
    • Set “index” equal to 1.
    • Declare a Boolean variable “true”.
    • Iterate a “while” loop,
      • Call the method “getLeftChildIndex()” on “index” and set the value to “childIndex”.
      • If “childIndex” is less than or equal to “lastIndex”,
        • Call “getIndexChild()” of “index” to “child”.
        • If the condition is true,
        • • Call “getRightChildIndex()” on “index” and set the result value to “childIndex”.
          • Call the method “getRightChild()” on “index” and set the value to “child”.
        • If the condition is true,
        • • Set “child” at “index”.
          • Set “childIndex” to “index”.
        • Else,
        • • Set “false” to “more”.
      • Else,
        • Set “false” to “more”.
        • • • Set “root” to “index” using “set”.
  • Define a method “empty()”,
    • Return “true” if “size” of “element” equal to 1,
  • Define the method “getLeftChildIndex()”,
    • Return the index.
  • Define the method “getRightChildIndex()”,
    • Return the index.
  • Define the method “getParentIndex()”,
    • Return the index.
  • Define the method “getLeftChild()”,
    • Return the element.
  • Define the method “getRightChild()”,
    • Return the element.
  • Define the method “getParent()”,
    • Return the element.

Filename: “MinHeapTester.java”

This code snippet creates a class “MinHeapTester”. In the code,

• Import the required packages.
• Define a class “MinHeapTester”.
  • Define the “main” method.
    • Declare a “MinHeap” named “heap”.
    • Add elements to “heap” using “add()” method.
    • Remove an element from “heap” and store it in a string variable “top”.
    • Print the value of “top”.
    • Print the expected value of “top”.
    • Remove an element from “heap” and store it in a string variable “top”.
    • Print the value of “top”.
    • Print the expected value of “top”.
    • Remove an element from “heap” and store it in a string variable “top”.
    • Print the value of “top”.
    • Print the expected value of “top”.