2017.11.1

果然一遇到連結串列就剪不清理還亂。一會兒就徹底懵了。

大致思路就是先判斷有沒有重複的，

如果有重複的，就全部刪除

如果沒有重複的，就下一個。

呵呵，道理我都懂啊，我就是寫不出來程式碼啊

/**
 * Definition for ListNode
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */


public class Solution {
    /*
     * @param head: head is the head of the linked list
     * @return: head of the linked list
     */
	public static ListNode deleteDuplicates(ListNode head) {
        // write your code here
		if(head == null ||head.next == null){
			return head;
		}
		ListNode myHead = new ListNode(-1);
		myHead.next = head;
		//表示當前遍歷節點的上一個節點
		ListNode flag = myHead;
		//當前的值
		
		while(head!= null){
			int tmp = head.val;
			if(head.next == null || head.next.val != tmp){
				flag.next = head;
				flag = head;
				head = head.next;
				continue;
			}
			while(head != null && head.val == tmp){
				head = head.next;
			}
			flag.next = head;
		}
		return myHead.next;
    }
}