/***************************************************************************
* Author: Isai Damier
* Title: Singly Linked List
* Project: geekviewpoint
* Package: datastructure
*
* Description: A LinkedList is a data structure that allows access
* to a collection of data using pointers/references. While an
* array can also be defined as above, LinkedLists and arrays differ
* in how they are stored in memory and in the operations they
* allow. Unlike an array that must be stored in a block of memory,
* the nodes of a LinkedList can be stored anywhere because each
* node has a reference to the node that succeeds it. Because the
* nodes are stored so loosely, inserting nodes into a LinkedList
* is easy; whereas in an array, all the succeeding elements must
* be shifted. Of course, insertion also means changing the size of
* the array, which means creating the entire array anew.
*
* Perhaps the greatest beauty of LinkedList is that it allows
* accessing an entire sequence of nodes using only one variable:
* a reference to the first node in the sequence.
*
* Countless operations can be performed on LinkedLists. Following
* are a few, ranging from the common to the very interesting.
**************************************************************************/
public class SinglyLinkedList {
Node head = null;
Node tail = null;
/*****************************************************************
* Time Complexity of Solution:
* O(n).
*
* Description: Swap the given elements if they both exist. Return
* true for success, false for failure. If either of the inputs
* has duplicates, this function swaps the first occurrences only.
*****************************************************************/
public boolean swap(int a, int b) {
Node A, B;//sometimes Java sucks: Should be able to declare in if.
if (null != (A = find(a)) && null != (B = find(b))) {
A.data = b;
B.data = a;
return true;
}
return false;
}
}
public class SinglyLinkedListTest {
/**
* Test of swap method, of class SinglyLinkedList.
*/
@Test
public void testSwap() {
System.out.println("swap");
int[] input = {9, 4, 5, 2, 1, 12, 6, 7, 4, 8, 3, 0, 16, 19, 11};
SinglyLinkedList linkedList = new SinglyLinkedList();
for (int i = 0; i < input.length; i++) {
linkedList.addToTail(input[i]);
}
linkedList.swap(9, 11);
int[] expected = {11, 4, 5, 2, 1, 12, 6, 7, 4, 8, 3, 0, 16, 19, 9};
assertTrue(Arrays.equals(expected, linkedList.toArray()));
linkedList.swap(1, 7);
int[] exp = {11, 4, 5, 2, 7, 12, 6, 1, 4, 8, 3, 0, 16, 19, 9};
assertTrue(Arrays.equals(exp, linkedList.toArray()));
}
}
