31. Next Permutation

31. Next Permutation/Program.cs

@@ -0,0 +1,30 @@
+var sol = new Solution();
+
+var cases = new (int[] input, int[] expected)[]
+{
+	(new[] { 1, 2, 3 }, new[] { 1, 3, 2 }),
+	(new[] { 3, 2, 1 }, new[] { 1, 2, 3 }),
+	(new[] { 1, 1, 5 }, new[] { 1, 5, 1 })
+};
+
+foreach (var (input, expected) in cases)
+{
+	var nums = (int[])input.Clone();
+	sol.NextPermutation(nums);
+	var status = AreEqual(nums, expected) ? "ok" : "fail";
+	Console.WriteLine($"{Format(input)} -> {Format(nums)} (expected: {Format(expected)}) {status}");
+}
+
+static string Format(int[] nums) => $"[{string.Join(",", nums)}]";
+
+static bool AreEqual(int[] left, int[] right)
+{
+	if (left.Length != right.Length)
+		return false;
+	for (var i = 0; i < left.Length; i++)
+	{
+		if (left[i] != right[i])
+			return false;
+	}
+	return true;
+}