0082. Remove Duplicates from Sorted List II

Author: coderbean

markdown/0082. Remove Duplicates from Sorted List II.md

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+### [82\. Remove Duplicates from Sorted List II](https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/)
+
+Difficulty: **Medium**
+
+
+Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only _distinct_ numbers from the original list.
+
+**Example 1:**
+
+```
+Input: 1->2->3->3->4->4->5
+Output: 1->2->5
+```
+
+**Example 2:**
+
+```
+Input: 1->1->1->2->3
+Output: 2->3
+```
+
+
+#### Solution
+
+Language: **Java**
+
+```java
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ * int val;
+ * ListNode next;
+ * ListNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public ListNode deleteDuplicates(ListNode head) {
+        if (head == null) {
+            return null;
+        }
+        ListNode fakeHead = new ListNode(0);
+        fakeHead.next = head;
+        ListNode pre = fakeHead;
+        ListNode curr = head;
+        while (curr != null) {
+            while (curr.next != null && curr.val == curr.next.val) {
+                curr = curr.next;
+            }
+            if (pre.next == curr) { // 说明该次循环没有重复元素
+                pre = pre.next;
+            } else {
+                pre.next = curr.next;
+            }
+            curr = curr.next;
+​
+        }
+        return fakeHead.next;
+    }
+}
+```
+![pic](https://raw.githubusercontent.com/PicGoBed/PicBed/master/2019-07-29-bjF2FD.jpg)