var coords = File .ReadAllLines(Path.Combine(Path.GetDirectoryName(Util.CurrentQueryPath), @"06_input.txt")) .Where(p => !string.IsNullOrWhiteSpace(p)) .Select(l => (int.Parse(l.Split(',')[0].Trim()), int.Parse(l.Split(',')[1].Trim())) ) .ToList(); int[][] d = new int[2][]; for (int i = 0; i < 2; i++) { var minX = coords.Min(p => p.Item1)-i; var maxX = coords.Max(p => p.Item1)+i; var minY = coords.Min(p => p.Item2)-i; var maxY = coords.Max(p => p.Item2)+i; int[,] map = new int[1+maxX-minX, 1+maxY-minY]; d[i] = new int[coords.Count]; for (int x = minX; x <= maxX; x++) for (int y = minX; y <= maxY; y++) { var s = coords.Select((c, idx) => new { I = idx, D = Math.Abs(c.Item1 - x) + Math.Abs(c.Item2 - y), V = c }).OrderBy(c => c.D).ToList(); if (s[0].D == s[1].D) { map[x-minX, y-minY]=-1; continue; } d[i][s[0].I]++; map[x-minX, y-minY]=s[0].I; } //map.Dump(); } //d[0].Zip(d[1], (a, b) => (a, b)).Dump(); d[0].Zip(d[1], (a, b) => (a, b)).Where(p => p.a == p.b).Max().a.Dump();