LeetCode-Remove Duplicates from Sorted List II

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

For example,
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.

public ListNode deleteDuplicates(ListNode head) {
        ListNode root = new ListNode(0);
        root.next = head;
        head = root;
        while (root.next != null) {
        	int val = root.next.val;
        	ListNode pNode = root.next.next;
        	while (pNode != null) {
        		if (val != pNode.val) {
        			break;
        		}
        		pNode = pNode.next;
        	}
        	if (pNode == root.next.next) {
        		root = root.next;
        	} else {
        		root.next = pNode;
        	}
        }
        return head.next;
    }