RemoveDuplicatesFromSortedList.java

/**
 * Given a sorted linked list, delete all duplicates such that each element appear only once.
 * <p>
 * For example,
 * Given 1->1->2, return 1->2.
 * Given 1->1->2->3->3, return 1->2->3.
 * <p>
 * Accepted.
 */
public class RemoveDuplicatesFromSortedList {

    public ListNode deleteDuplicates(ListNode head) {
        ListNode node = head;
        while (node != null && node.next != null) {
            if (node.val == node.next.val) {
                ListNode tmp = node.next;
                node.next = tmp.next;
                tmp.next = null;
            } else {
                node = node.next;
            }
        }
        return head;
    }

    public static class ListNode {

        int val;
        ListNode next;

        ListNode(int x) {
            val = x;
        }

        @Override
        public boolean equals(Object obj) {
            if (obj instanceof ListNode) {
                ListNode node = (ListNode) obj;
                return this.next == null && node.next == null || this.val == node.val && (this.next != null) && this.next.equals(node.next);
            }
            return false;
        }

    }

}