82. Remove Duplicates from Sorted List II

Author: Kai Yang

82.RemoveDuplicatesFromSortedListII.Test.cs

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+using System;
+using System.Linq;
+using Newtonsoft.Json;
+using NUnit.Framework;
+
+[TestFixture]
+public class TestClass : TestClassBase
+{
+    [TestCase(10, 10, 1000)]
+    public void TestMethod(int maxLength, int maxValue, int repeatTimes)
+    {
+        Repeat(repeatTimes, () => {
+            var listValues = GenerateIntegerArray(maxLength, maxValue);
+            Array.Sort(listValues);
+            var head = ListNode.GetHead(listValues);
+            var result = new Solution().DeleteDuplicates(head);
+            Assert.AreEqual(JsonConvert.SerializeObject(listValues.Where(v => listValues.Count(v2 => v2 == v) == 1)), ListNode.Serialize(result), JsonConvert.SerializeObject(listValues));
+        });
+    }
+}

82.RemoveDuplicatesFromSortedListII.cs

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+public class Solution {
+    private ListNode newHead;
+    private ListNode last;
+    private ListNode candidate;
+    private int count;
+
+    public ListNode DeleteDuplicates(ListNode head) {
+        while (head != null)
+        {
+            if (candidate == null || candidate.val != head.val)
+            {
+                TryAppend();
+                candidate = head;
+                count = 1;
+            }
+            else
+            {
+                ++count;
+            }
+
+            head = head.next;
+        }
+        TryAppend();
+        if (last != null) last.next = null;
+        return newHead;
+    }
+
+    private void TryAppend()
+    {
+        if (count == 1)
+        {
+            if (newHead == null)
+            {
+                newHead = last = candidate;
+            }
+            else
+            {
+                last.next = candidate;
+                last = last.next;
+            }
+        }
+    }
+}