https://leetcode.com/problems/longest-consecutive-sequence/

Author: harshitgindra

HardProblems/Longest Consecutive Sequence.cs

@@ -0,0 +1,49 @@
+namespace LeetCode.MediumProblems
+{
+    internal class LongestConsecutiveSequence
+    {
+        public int LongestConsecutive(int[] nums)
+        {
+            HashSet<int> numSet = new HashSet<int>(nums);
+            int maxSequenceLength = 0;
+
+            foreach (int num in numSet)
+            {
+                // Check if current number is the start of a sequence
+                if (!numSet.Contains(num - 1))
+                {
+                    int currentLength = 1;
+
+                    // Extend the sequence forward
+                    while (numSet.Contains(num + currentLength))
+                    {
+                        currentLength++;
+                    }
+
+                    maxSequenceLength = Math.Max(maxSequenceLength, currentLength);
+                }
+            }
+
+            return maxSequenceLength;
+        }
+
+
+        [Test(Description = "https://leetcode.com/problems/longest-consecutive-sequence/")]
+        [Category("Medium")]
+        [Category("LeetCode")]
+        [Category("Longest Consecutive Sequence")]
+        [TestCaseSource(nameof(Input))]
+        public void Test1((int Output, int[] Input) item)
+        {
+            var response = LongestConsecutive(item.Input);
+            Assert.That(response, Is.EqualTo(item.Output));
+        }
+
+        public static IEnumerable<(int Output, int[] Input)> Input =>
+            new List<(int Output, int[] Input)>()
+            {
+                (4, [100, 4, 200, 1, 3, 2]),
+                (2, [0, -1]),
+            };
+    }
+}