TreeProblems.java

/*
 * *** Ryan Compas / COMP 272-001 ***
 *
 * This java file contains several simple tree problems that need to be
 * codified. These routines  must use the TreeMap and TreeSet library
 * classes from the Java Collection Framework.
 *
 */

import java.util.*;

public class TreeProblems {

  /**
   * Method different()
   *
   * Given two TreeSets of integers, return a TreeSet containing all elements 
   * that are NOT in both sets. In other words, return a TreeSet of all the
   * elements that are in one set but not the other.
   */
  
  public static Set<Integer> different(Set<Integer> setA, Set<Integer> setB) {

    // INSERT CODE HERE - DO NOT FORGET TO PLACE YOUR NAME ABOVE
    //
    // This can be done numerous ways, but once such will only that
    // *several* lines of code. Hint: create two temporary TreeSets and utilize the
    // methods retainAll(), addAll(), and removeAll(). But in the end, get something to work.

    // create temporary TreeSets
    Set<Integer> treeSetA= new TreeSet<>(setA);
    Set<Integer> treeSetB= new TreeSet<>(setB);

    // make treeSetA retain common nodes and remove them from setA
    treeSetA.retainAll(treeSetB);
    setA.removeAll(treeSetA);

    // remove common nodes in treeSetA from treeSetB and add remaining treeSetB nodes to setA
    treeSetB.removeAll(treeSetA);
    setA.addAll(treeSetB);

    return setA;
  }


  /**
   * Method removeEven()
   *
   * Given a treeMap with the key as an integer, and the value as a String,
   * remove all <key, value> pairs where the key is even. 
   */

  public static void removeEven(Map<Integer, String> treeMap) {

    // create iterator to move through the treeMap
    Iterator<Map.Entry<Integer, String>> iterator = treeMap.entrySet().iterator();

    // iterate through treeMap, deleting keys if they are even
    while (iterator.hasNext()){
      Map.Entry<Integer, String> entry = iterator.next();
      if (entry.getKey() % 2 == 0){
        iterator.remove();
      }
    }
    return;
  }


  /**
   * Method treesEqual()
   *
   * Given two treeMaps, each with the key as an integer, and the value as a String,
   * return a boolean value indicating if the two trees are equal or not.
   */

  public boolean treesEqual(Map<Integer, String> tree1,Map<Integer, String> tree2 ) {

    // use equals method to compare trees
    if (tree1.equals(tree2)){
      return true;
    }
    else {
      return false;
    }
  }
} // end treeProblems class