LC#203 remove given value from linked list,iterative and recursive solution

Author: NirmalSilwal

Leetcode/leetcodeTags/LinkedList/RemoveLinkedListElement203.java

@@ -0,0 +1,61 @@
+package LinkedList;
+
+public class RemoveLinkedListElement203 {
+
+	public class ListNode {
+		int val;
+		ListNode next;
+
+		ListNode() {
+		}
+
+		ListNode(int val) {
+			this.val = val;
+		}
+
+		ListNode(int val, ListNode next) {
+			this.val = val;
+			this.next = next;
+		}
+	}
+
+	// O(N) time, O(1) space
+	public ListNode removeElements(ListNode head, int val) {
+
+		if (head == null)
+			if (head == null)
+				return null;
+
+		ListNode dummy = new ListNode(-1);
+		dummy.next = head;
+		ListNode tail = dummy;
+
+		while (head != null) {
+			if (head.val == val) {
+				ListNode temp = head.next;
+				tail.next = temp;
+				head = temp;
+			} else {
+				head = head.next;
+				tail = tail.next;
+			}
+		}
+
+		return dummy.next;
+	}
+
+	// recursive approach
+	public ListNode removeElementsRecursive(ListNode head, int val) {
+
+		if (head == null)
+			return null;
+
+		head.next = removeElementsRecursive(head.next, val);
+
+		// can also write it using ternary operator
+		if (head.val == val) {
+			return head.next;
+		} else
+			return head;
+	}
+}