Add Q1630 solution

LeetCode.Tests/Q1630_ArithmetricSubarraysTests.cs

@@ -0,0 +1,18 @@
+namespace LeetCode.Tests;
+
+public class Q1630Tests
+{
+    [Theory]
+    [InlineData(new int[] { 4, 6, 5, 9, 3, 7 }, new int[] { 0, 0, 2 }, new int[] { 2, 3, 5 }, new bool[] { true, false, true })]
+    [InlineData(new int[] { -12, -9, -3, -12, -6, 15, 20, -25, -20, -15, -10 }, new int[] { 0, 1, 6, 4, 8, 7 }, new int[] { 4, 4, 9, 7, 9, 10 }, new bool[] { false, true, false, false, true, true })]
+    public void CheckArithmeticSubarrays_ValidInput_ReturnsCorrectResult(int[] nums, int[] l, int[] r, bool[] expectedResult)
+    {
+        // Arrange
+
+        // Act
+        var actualResult = Q1630.CheckArithmeticSubarrays(nums, l, r);
+
+        // Assert
+        Assert.Equal(expectedResult, [.. actualResult]);
+    }
+}

LeetCode/Q1630_ArithmetricSubarrays.cs

@@ -0,0 +1,41 @@
+namespace LeetCode;
+
+public class Q1630
+{
+    // Time Complexity: O(n * m)
+    // Space Complexity: O(n)
+
+    public static IList<bool> CheckArithmeticSubarrays(int[] nums, int[] l, int[] r)
+    {
+        List<bool> result = [];
+        for (var i = 0; i < l.Length; i++) // O(n * m)
+        {
+            var subArray = ExtractSubArray(nums, l[i], r[i]); // O(m)
+            result.Add(IsArithmetric(subArray)); // O(m)
+        }
+        return result;
+    }
+
+    private static List<int> ExtractSubArray(int[] nums, int l, int r) // O(m)
+    {
+        List<int> subArray = new(r - l + 1);
+        for (var p = l; p <= r;  p++)
+            subArray.Add(nums[p]);
+        return subArray;
+    }
+
+    private static bool IsArithmetric(List<int> arr) // O (m)
+    {
+        if (arr.Count == 1)
+            return true;
+
+        var sortedArr = arr.OrderBy(x => x).ToList(); // O(m log m)
+        var commonDifference = sortedArr[1] - sortedArr[0];
+        for (var i = 2; i < sortedArr.Count; i++) // O (m)
+        {
+            if (sortedArr[i] - sortedArr[i - 1] != commonDifference)
+                return false;
+        }
+        return true;
+    }
+}