exo2/Main.java

   1 import java.util.ArrayList;
   2 import java.util.LinkedList;
   3 import java.util.ListIterator;
   4 import java.util.concurrent.TimeUnit;
   5
   6 class Main {
   7
   8     private static <E> void addMiddle(ArrayList<E> array, E value) {
   9         int mid = array.size() / 2;
  10         array.add(mid + 1, value);
  11     }
  12
  13     private static <E> void addMiddle(LinkedList<E> list, E value) {
  14         int mid = list.size() / 2;
  15         list.add(mid + 1, value);
  16     }
  17
  18     /**
  19      * Should mimic the collection add(int index, T value) method
  20      * @param  array [description]
  21      * @param  value [description]
  22      * @return       [description]
  23      */
  24     private static <E> void addMiddleIter(ArrayList<E> array, E value) {
  25         int mid = array.size() / 2;
  26         ListIterator<E> iter = array.listIterator();
  27         int i = 0;
  28         // go to the element at mid index
  29         while (iter.hasNext() && i < mid) {
  30             iter.next();
  31             i++;
  32         }
  33         iter.next(); // Insert before mid + 1
  34         iter.add(value);
  35
  36     }
  37
  38     /**
  39      * Should mimic the collection add(int index, T value) method
  40      * @param  list  [description]
  41      * @param  value [description]
  42      * @return       [description]
  43      */
  44     private static <E> void addMiddleIter(LinkedList<E> list, E value) {
  45         int mid = list.size() / 2;
  46         ListIterator<E> iter = list.listIterator();
  47         int i = 0;
  48         // go to the element at mid index
  49         while (iter.hasNext() && i < mid) {
  50             iter.next();
  51             i++;
  52         }
  53         iter.next(); // Insert before mid + 1
  54         iter.add(value);
  55     }
  56
  57     private static <E> void addNEMiddle(ArrayList<E> array, int Nelements) {
  58         ListIterator<E> iter = array.listIterator();
  59         int i = 0;
  60         // go to the element at the middle index
  61         while (iter.hasNext() && i < array.size() / 2) {
  62             iter.next();
  63             i++;
  64         }
  65         iter.next(); // Insert before mid + 1
  66         for (int j = 0; j < Nelements; j++) {
  67             iter.add((E)new Object());
  68         }
  69     }
  70
  71     private static <E> void addNEMiddle(LinkedList<E> list, int Nelements) {
  72         ListIterator<E> iter = list.listIterator();
  73         int i = 0;
  74         // go to the element at the middle index
  75         while (iter.hasNext() && i < list.size() / 2) {
  76             iter.next();
  77             i++;
  78         }
  79         iter.next(); // Insert before mid + 1
  80         for (int j = 0; j < Nelements; j++) {
  81             iter.add((E)new Object());
  82         }
  83     }
  84
  85     /**
  86      * The main() function
  87      * @param String[] args main() function arguments array
  88      */
  89     public static void main(String[] args) {
  90         ArrayList<Integer> array = new ArrayList<Integer>();
  91         LinkedList<Integer> list = new LinkedList<Integer>();
  92
  93         for (int i = 0; i < 1000000; i++) {
  94             array.add(i);
  95             list.add(i);
  96         }
  97
  98         long startTime = System.nanoTime();
  99         //for (int i = 0; i < 100000; i++) {
 100         //    addMiddleIter(array, i);
 101         //}
 102         addNEMiddle(array, 100000);
 103         long stopTime = System.nanoTime();
 104         long execTime = stopTime - startTime;
 105         //System.out.println("Insert time in the middle of the ArrayList: " + TimeUnit.NANOSECONDS.toSeconds(execTime) + " s");
 106         System.out.println("Insert time in the middle of the ArrayList: " + execTime + " ns");
 107
 108         startTime = System.nanoTime();
 109         //for (int i = 0; i < 100000; i++) {
 110         //    addMiddleIter(list, i);
 111         //}
 112         addNEMiddle(list, 100000);
 113         stopTime = System.nanoTime();
 114         execTime = stopTime - startTime;
 115         //System.out.println("Insert time in the middle of the LinkedList: " + TimeUnit.NANOSECONDS.toSeconds(execTime) + " s");
 116         System.out.println("Insert time in the middle of the LinkedList: " + execTime + " ns");
 117     }
 118 }