Session 3 Homework Refactor

src/JavaBasicsLab/MainClassForFirstSession.java

@@ -1,5 +1,8 @@
 package JavaBasicsLab;
 
+import java.util.ArrayList;
+import java.util.Random;
+
 import static java.lang.Math.pow;
 
 public class MainClassForFirstSession {
@@ -21,21 +24,23 @@ public static void main(String[] args) {
 // printArray(vector3);
 // findMaxIntNumber(vector3);
 
+// int[] array = {1, 2, 3, 4, 5, 6, 8, 9, 10, 13, 15, 18, 19, 20, 23, 25, 26, 28, 30, 34, 35, 36, 38, 39, 40};
 
- int[] array = {1, 2, 3, 4, 5, 6, 8, 9, 10, 13, 15, 18, 19, 20, 23, 25, 26, 28, 30, 34, 35, 36, 38, 39, 40};
+ int[] array = createRandomOrderedNumbers(4000, 4100);
+// printArray(array);
 
  long startTime = System.nanoTime();
- twoNumbersEqualX1(array, 37);
+ twoNumbersEqualX1(array, 3700);
  long endTime = System.nanoTime();
  long duration1 = (endTime - startTime);
 
  long startTime2 = System.nanoTime();
- twoNumbersEqualX2(array, 37);
+ twoNumbersEqualX2v2(array, 3700);
  long endTime2 = System.nanoTime();
  long duration2 = (endTime2 - startTime2);
 
  long startTime3 = System.nanoTime();
- twoNumbersEqualX3(array, 37);
+ twoNumbersEqualX3(array, 3700);
  long endTime3 = System.nanoTime();
  long duration3 = (endTime3 - startTime3);
 
@@ -240,6 +245,24 @@ private static boolean gasesteNumar(int[] arr, int numarCeTrebuieCautat) {
  return false;
  }
 
+ private static int[] gasesteNumar2(int[] arr, int numarCeTrebuieCautat){
+ int length = arr.length/2;
+ if(numarCeTrebuieCautat < arr[length])
+ {
+ int[] arrToBeReturned = new int[length];
+ System.arraycopy(arr, 0, arrToBeReturned, 0, length);
+ return arrToBeReturned;
+ } else if (numarCeTrebuieCautat > arr[length]){
+ int[] arrToBeReturned = new int[length];
+ System.arraycopy(arr, length , arrToBeReturned, 0, length);
+ return arrToBeReturned;
+ } else {
+ int[] result = new int[1];
+ result[0] = numarCeTrebuieCautat;
+ return result;
+ }
+ }
+
  private static boolean twoNumbersEqualX2(int[] arr, int sumaDorita) {
  int numarCeTrebuieCautat;
  for (int i : arr) {
@@ -249,6 +272,23 @@ private static boolean twoNumbersEqualX2(int[] arr, int sumaDorita) {
  return false;
  }
 
+ private static boolean twoNumbersEqualX2v2(int[] arr, int sumaDorita) {
+ int numarCeTrebuieCautat;
+ for (int i : arr) {
+ numarCeTrebuieCautat = sumaDorita - i;
+ int[] searchArray = arr;
+ do{
+ searchArray = gasesteNumar2(searchArray, numarCeTrebuieCautat);
+ }
+ while ( searchArray.length > 1);
+ if(searchArray[0] == numarCeTrebuieCautat){
+ return true;
+ }
+
+ }
+ return false;
+ }
+
  private static boolean twoNumbersEqualX3(int[] arr, int sumaDorita) {
  int sumaCurenta;
 
@@ -268,4 +308,25 @@ private static boolean twoNumbersEqualX3(int[] arr, int sumaDorita) {
  }
  return false;
  }
+
+ // Method returns a random array of your desired size and your desired range.
+ // I don't recommend trying to understand how this method works :)
+ // But if you want to, go for it!
+ public static int[] createRandomOrderedNumbers(int size, int range) {
+ if(size > range) {
+ System.out.println("ERROR, you cannot create an array of length " + size + " with random unique numbers between 0-"+ range);
+ return new int[1];
+ }
+ ArrayList<Integer> numbers = new ArrayList<Integer>();
+ Random r = new Random();
+ while (numbers.size() < size) {
+ int nextRandom = r.nextInt(range);
+ if (!numbers.contains(nextRandom)) {
+ numbers.add(nextRandom);
+ }
+ }
+ return numbers.stream().sorted().mapToInt(i -> i).toArray();
+
+ }
+
 }