Question

Write a program to compute intersection of two sorted array of integers and compute the CPU time for different sets of unsigned integers generated by a random number generator using HASH SET.

Test this using the same data sets: atleast 3 of size 1000 integers, atleast 3 of size 10000 integers, atleast 3 of size 100000 integers, atleast 3 of one million integers and atleast 3 of size 10 million integers

DONT FORGET CPU TIME FOR EACH ONE

Answer 1

import java.util.ArrayList;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;

/**
* This program is written in java language which generates two unsigned integer arrays
* and then generate intersection of two arrays
*
*/
public class GenerateArrayCPUTimeAndIntersection {

   public static void main(String[] args) {
       final int iteration = 3; //for each dataset size 3 times intersection iteration
       Integer[] array1 = null; // stores first array generated by dataset size
       Integer[] array2 = null; // stores second array generated by dataset size
       long time1, time2;
       long arrayTime1, arrayTime2;

       List<Integer> dataSetSizeList = new ArrayList<>(5);
       dataSetSizeList.add(1000);
       dataSetSizeList.add(10000);
       dataSetSizeList.add(100000);
       dataSetSizeList.add(1000000);
       dataSetSizeList.add(10000000);

       for (Integer dataSetSize : dataSetSizeList) {
           for (int i = 1; i <= iteration; i++) {
               System.out.println("*******************************************");
               System.out.println("Iteration number: " + i);
               System.out.println("Dataset size: " + dataSetSize);
               time1 = System.currentTimeMillis();
               array1 = getUnsingedNumbers(dataSetSize);
               time2 = System.currentTimeMillis();
               arrayTime1 = time2 - time1;
               time1 = System.currentTimeMillis();
               array2 = getUnsingedNumbers(dataSetSize);
               time2 = System.currentTimeMillis();
               arrayTime2 = time2 - time1;
               System.out.println("First Array Generation Time: " + arrayTime1 + " millisecond(s)");
               System.out.println("Second Array Generation Time: " + arrayTime2 + " millisecond(s)");
               List<Integer> intersectValues = generateIntersection(array1, array2);
               System.out.println(intersectValues);
           }
       }
       System.out.println("*******************************************");
   }

   /**Generates intersection of array1 and array2
   * @param array1
   * @param array2
   * @return
   */
   public static List<Integer> generateIntersection(Integer[] array1, Integer[] array2)
   {
       HashSet<Integer> set = new HashSet<>();
       List<Integer> intersectValues = new LinkedList<Integer>();
       for (int i = 0; i < array1.length; i++)
           set.add(array1[i]);

       for (int i = 0; i < array2.length; i++) {
           if (set.contains(array2[i])) {
               intersectValues.add(array2[i]);
           }
       }
       return intersectValues;
   }

   /**This method generates unsigned numbers array based on passed size
   * @param arraySize
   * @return
   */
   public static Integer[] getUnsingedNumbers(int arraySize) {
       HashSet<Integer> set = new HashSet<Integer>();
       Random random = new Random();
       while(set.size() <= arraySize){
           int thisOne = random.nextInt((Integer.MAX_VALUE - 1) + 1) + 1;
           set.add(thisOne);
       }
       Integer[] array = new Integer[set.size()];
       set.toArray(array);
       return array;
   }
}