| 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 | } |