// 1, 2, 3 // 2, 1, 3 // 3, 1, 2 // 1, 3, 2 // 2, 3, 1 // 3, 2, 1 // Total permutations: 6 using System; using System.Linq; public static class GeneratePermutationsIteratively { public static void Main() { var num = int.Parse(Console.ReadLine()); var numberOfPerm = 1; var elements = Enumerable.Range(1, num).ToArray(); var workArr = Enumerable.Range(0, elements.Length + 1).ToArray(); PrintPerm(elements); var index = 1; while (index < elements.Length) { workArr[index]--; var j = 0; if (index % 2 == 1) { j = workArr[index]; } SwapInts(ref elements[j], ref elements[index]); index = 1; while (workArr[index] == 0) { workArr[index] = index; index++; } numberOfPerm++; PrintPerm(elements); } Console.WriteLine($"Total permutations: {numberOfPerm}"); } private static void PrintPerm(int[] elements) { Console.WriteLine(string.Join(", ", elements)); } private static void SwapInts(ref int a, ref int b) { a ^= b; b ^= a; a ^= b; } }