reverse single linked list

Reverse a single linked list

Author: singhvirendra18gmailcom

ReverseSingleLinkedList.java

@@ -0,0 +1,145 @@
+package collection;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+public class ReverseSingleLinkedList<T> {
+
+	private Node<T> head;
+
+	public ReverseSingleLinkedList() {
+
+	}
+
+	public String toString() {
+		StringBuffer toReturn = new StringBuffer("[");
+		Node<T> tempHead = head;
+		if (tempHead != null) {
+			toReturn.append(tempHead.getElement());
+			while (tempHead.getNext() != null) {
+				tempHead = tempHead.getNext();
+				toReturn.append(", ").append(tempHead.getElement());
+
+			}
+		}
+		toReturn.append("]");
+		return toReturn.toString();
+	}
+
+	public Node<T> getHead() {
+		return head;
+	}
+
+	public void setHead(Node<T> head) {
+		this.head = head;
+	}
+
+	public T add(T data) {
+		if (data == null) {
+			return null;
+		}
+		Node<T> n = new Node<T>(data, null);
+		Node<T> tempHead = head;
+		if (tempHead == null) {
+			tempHead = n;
+			head = tempHead;
+		} else {
+			while (tempHead.getNext() != null) {
+				tempHead = tempHead.getNext();
+			}
+
+			tempHead.setNext(n);
+		}
+		return data;
+	}
+
+	public T remove(T data) {
+
+		Node<T> tempHead = head;
+		Node<T> previous = head;
+
+		if (tempHead == null) {
+			return null;
+		} else {
+
+			while (tempHead != null) {
+				if (tempHead.getElement().equals(data)) {
+					previous.setNext(tempHead.getNext());
+					break;
+				}
+				previous = tempHead;
+				tempHead = tempHead.next;
+			}
+		}
+		return data;
+	}
+
+	 public void reverse() {
+	        Node<T> prev = null;
+	        Node<T> current = head;
+	        Node<T> next = null;
+	        while (current != null) {
+	            next = current.next;
+	            current.next = prev;
+	            prev = current;
+	            current = next;
+	        }
+	        head = prev;
+	        
+	    }
+
+	@Test
+	public void test() {
+		ReverseSingleLinkedList<String> list = new ReverseSingleLinkedList<>();
+		System.out.println(list);
+
+		System.out.println("-----------------------------");
+
+		assertTrue("Hello".equalsIgnoreCase(list.add("Hello")));
+		assertTrue("Saty".equalsIgnoreCase(list.add("Saty")));
+		assertTrue("vir".equalsIgnoreCase(list.add("vir")));
+		assertTrue(null == list.add(null));
+
+		assertTrue("Man".equalsIgnoreCase(list.add("Man")));
+
+		System.out.println(list);
+
+		System.out.println("-----------------------------");
+		assertTrue("vir".equalsIgnoreCase(list.remove(("vir"))));
+		System.out.println(list);
+		
+		System.out.println("-----------------------------");
+		list.reverse();
+		System.out.println(list);
+
+	}
+
+	private class Node<T> {
+		private T element;
+		private Node<T> next;
+
+		public T getElement() {
+			return element;
+		}
+
+		public void setElement(T element) {
+			this.element = element;
+		}
+
+		public Node<T> getNext() {
+			return next;
+		}
+
+		public void setNext(Node<T> next) {
+			this.next = next;
+		}
+
+		public Node(T element, Node<T> next) {
+			this.element = element;
+			this.next = next;
+		}
+
+	}
+
+}