力扣：82. 删除排序链表中的重复元素 II

LeetCode/src/main/java/com/code/leet/study/t20210209/DeleteDuplicates.java

@@ -0,0 +1,41 @@
+package com.code.leet.study.t20210209;
+
+import com.code.leet.entiy.ListNode;
+import org.omg.CORBA.FREE_MEM;
+
+/**
+ * 给定一个排序链表，删除所有重复的元素，使得每个元素只出现一次。
+ */
+public class DeleteDuplicates {
+    /**
+     * 82. 删除排序链表中的重复元素 II
+     */
+    public ListNode deleteDuplicates(ListNode head) {
+        if (head == null || head.next == null) {
+            return head;
+        }
+        ListNode front = new ListNode(-1);
+        ListNode temp = front;
+        int same = head.val;
+        boolean flag = false;
+        while (head.next != null) {
+            if (head.val == head.next.val) {
+                head.next = head.next.next;
+                same = head.val;
+                flag = true;
+            } else if (flag && head.val == same) {
+                head = head.next;
+            } else {
+                temp.next = head;
+                temp = temp.next;
+                head = head.next;
+            }
+        }
+        if (head.val == same) {
+            temp.next = null;
+        } else {
+            temp.next = head;
+        }
+        return front.next;
+    }
+}