using System; using System.Linq; // https://www.sololearn.com/Discuss/765302/?ref=app namespace SoloLearn { class Program { static void Main(string[] zephyr_koo) { // Assumption: 5-digit number foreach (int number in new int[] { 12345, 37691, 33333, 34563, 67548 }) { var strSorted = number.ToString().OrderBy(c => c).ToList(); int maxDigit = (int)Char.GetNumericValue(strSorted.Last()); int firstTwoSum = (int)Char.GetNumericValue(strSorted[0]) + (int)Char.GetNumericValue(strSorted[1]); Console.WriteLine( strSorted.Distinct().Count() == 1 ? GetPlainPattern(maxDigit) : GetTrianglePattern(maxDigit, maxDigit <= firstTwoSum)); Console.WriteLine(Environment.NewLine); } } static string GetPlainPattern(int digit) { return string.Concat(Enumerable.Repeat(digit, (digit * (digit + 1) / 2))); } ///

/// Print Triangle pattern by new-line insertion ///

/// /// NOTE 1: Arithmetic sum with a = digit, d = -1 // NOTE 2: Arithmetic sum with a = 1, d = 1 // NOTE 3: Environment.NewLine (\r\n) take 2 characters // NOTE 4: BEWARE! Side-effect which insert new line at specific gap /// /// /// /// static string GetTrianglePattern(int digit, bool isInverted) { var str = GetPlainPattern(digit); Enumerable.Range(1, digit - 1) .Select(n => (isInverted ? n * (2 * digit - n + 1) / 2 : // 1 n * (n + 1) / 2) + // 2 2 * (n - 1)) // 3 .ToList() .ForEach(i => str = str.Insert(i, Environment.NewLine)); // 4 return str; } } }

Number Triangle Display Challenge