The method which could be applied to Double Linked List

DoubleLinkedList.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
package com.chung;

public class DoubleLinkedList {
	DoubleNode head;
	DoubleNode tail;
	int size;//denotes size of list
	
	public int getSize() {
		return size;
	}

	public void setSize(int size) {
		this.size = size;
	}
	
	DoubleNode createDoubleLinkedList(int nodeValue) {
		head = new DoubleNode();
		DoubleNode node = new DoubleNode();
		node.setValue(nodeValue);
		node.setNext(null);
		node.setPrev(null);
		head = node;
		tail = node;
		size=1;// size =1
		return head;
	}
	
	
	
	void insertInLinkedList(int nodeValue, int location) {
		DoubleNode node = new DoubleNode();
		node.setValue(nodeValue);
		if (!existsLinkedList()) {
			System.out.println("The linked list does not exist!!");
			return; // Linked List does not exists
		} else if (location == 0) {// insert at first position
			node.setNext(head);
			node.setPrev(null);
			head.setPrev(node);
			head = node;
		} else if (location >= size) {// insert at last position
			node.setNext(null);
			tail.setNext(node);
			node.setPrev(tail);
			tail = node; // to keep track of last node
		} else {// insert at specified location
			DoubleNode tempNode = head;
			int index = 0;
			while (index < location - 1) {// loop till we reach specified node
				tempNode = tempNode.getNext();
				index++;
			}
			node.setPrev(tempNode);
			node.setNext(tempNode.getNext());
			tempNode.setNext(node);
			node.getNext().setPrev(node);
		}
		size++;
	}
	
	
	public boolean existsLinkedList() {
		//if head is not null retrun true otherwise return false
		return head!=null;
	}
	
	
	
	//Traverse the linked list from head to last
	void traverseLinkedList() {
		if(existsLinkedList()) {
			//System.out.println("Linked List now: ");
			DoubleNode tempNode=head;
			for(int i =0; i<size;i++) {
				
				System.out.print(tempNode.getValue());
				if(i!=size-1) {
					System.out.print(" -> ");
				}
				tempNode=tempNode.getNext();
			}
		}else {
			System.out.println("Linked List does not exists");
		}
		System.out.println("\n");
	}
	
	
	// Traverse the linked list from head to last
	void traverseLinkedListInReverseOrder() {
		if (existsLinkedList()) {
			DoubleNode tempNode = tail;
			for (int i = 0; i < size; i++) {
				System.out.print(tempNode.getValue());
				if (i != size-1) {
					System.out.print(" <- ");
				}
				tempNode = tempNode.getPrev();
			}
		} else {
			System.out.println("Linked List does not exists");
		}
		System.out.println("\n");
	}
	
	//delete whole linked list
	void deleteLinkedList() {
		System.out.println("\n\nDeleting Linked List...");
		DoubleNode tempNode = head;
		for (int i = 0; i < size; i++) {
			tempNode.setPrev(null);
			tempNode = tempNode.getNext();
		}
		
		head = null;
		tail = null;
		System.out.println("Linked List deleted successfully !");
	 }
	
	
	//Search for a node in linked list 
	boolean searchNode(int nodeValue) {
		if(existsLinkedList()) {
			DoubleNode tempNode=head;
			for(int i =0; i<size;i++) {
				if(tempNode.getValue()==nodeValue) {
					System.out.print("Found the node at locaiton: " + i);
					return true;
				}
				tempNode=tempNode.getNext();
			}
		}
		System.out.print("Node not found!! ");
		return false;
	}
	
	
	// Deletes a node having a given value
	public void deletionOfNode(int location) {
		if (!existsLinkedList()) {
			System.out.println("The linked list does not exist!!");// Linked List does not exists
			return;
		} else if (location == 0) { // we want to delete first element
			if (getSize() == 1) { // if this is the only node in this list
				head = tail = null;
				setSize(getSize() - 1);
				return;
			}else {
				head = head.getNext();
				head.setPrev(null);
				setSize(getSize() - 1);
			}
		} else if (location >= getSize()) { // If location is not in range or equal, then delete last node
			DoubleNode tempNode = tail.getPrev(); // temp node points to 2nd last node
			if (tempNode == head) { // if this is the only element in the list
				tail = head = null;
				setSize(getSize() - 1);
				return;
			}
			tempNode.setNext(null);
			tail = tempNode;
			setSize(getSize() - 1);

		} else { // if any inside node is to be deleted
			DoubleNode tempNode = head;
			for (int i = 0; i < location - 1; i++) {
				tempNode = tempNode.getNext(); // we need to traverse till we find the location
			}
			tempNode.setNext(tempNode.getNext().getNext()); // delete the required node
			tempNode.getNext().setPrev(tempNode);
			setSize(getSize() - 1);
		} // end of else

	}// end of method

}//end of class

DoubleNode.java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
package com.chung;

public class DoubleNode {

    private int value;
    private DoubleNode prev;
    private DoubleNode next;

    public int getValue() {
        return value;
    }

    public void setValue(int value) {
        this.value = value;
    }

    public DoubleNode getPrev() {
        return prev;
    }

    public void setPrev(DoubleNode prev) {
        this.prev = prev;
    }

    public DoubleNode getNext() {
        return next;
    }

    public void setNext(DoubleNode next) {
        this.next = next;
    }

    @Override
    public String toString() {
        return value + "";
    }
}