feat: solve part 1

14/ParabolicReflectorDish/Program.cs

@@ -1,2 +1,107 @@
-// See https://aka.ms/new-console-template for more information
-Console.WriteLine("Hello, World!");
+using System.Diagnostics;
+
+namespace ParabolicReflectorDish;
+
+public class Program
+{
+  public static async Task<int> Main(string[] args)
+  {
+    if (args.Length is 0)
+    {
+      Console.WriteLine("Please provide a path to the input file.");
+      return -1;
+    }
+
+    if (File.Exists(args[0]) is false)
+    {
+      Console.WriteLine("The provided file does not exist.");
+      return -2;
+    }
+
+    var input = await File.ReadAllLinesAsync(args[0]);
+
+    var stopwatch = new Stopwatch();
+    stopwatch.Start();
+
+    var result = Dish
+      .Parse(input)
+      .CalculateTotalLoad();
+
+    stopwatch.Stop();
+
+    Console.WriteLine($"The total load is {result}. ({stopwatch.ElapsedMilliseconds}ms)");
+
+    return (int)result;
+  }
+}
+
+public class Dish(
+  List<List<char>> rows
+)
+{
+  private const char RoundRockSymbol = 'O';
+  private const char SquareRockSymbol = '#';
+  private const char EmptySpaceSymbol = '.';
+
+  public List<List<char>> Rows { get; init; } = rows;
+
+  private List<List<char>> TiltDishToNorth(List<List<char>> rows)
+  {
+    var modifiedRows = rows.ToList();
+    var numOfColumns = modifiedRows[0].Count;
+    var numOfRows = modifiedRows.Count;
+
+    for (var currentColumnIndex = 0; currentColumnIndex < numOfColumns; currentColumnIndex++)
+    {
+      for (var currentRowIndex = 0; currentRowIndex < numOfRows; currentRowIndex++)
+      {
+        var current = modifiedRows[currentRowIndex][currentColumnIndex];
+
+        if (current is EmptySpaceSymbol)
+        {
+          for (var i = currentRowIndex + 1; i < numOfRows; i++)
+          {
+            var next = modifiedRows[i][currentColumnIndex];
+
+            if (next is SquareRockSymbol)
+            {
+              break;
+            }
+
+            if (next is RoundRockSymbol)
+            {
+              modifiedRows[currentRowIndex][currentColumnIndex] = RoundRockSymbol;
+              modifiedRows[i][currentColumnIndex] = EmptySpaceSymbol;
+              break;
+            }
+          }
+        }
+      }
+    }
+
+    return modifiedRows;
+  }
+
+  public long CalculateTotalLoad()
+  {
+    var rows = TiltDishToNorth(Rows);
+    rows.Reverse();
+
+    return rows
+      .Select((r, index) =>
+      {
+        var numOfRoundRocks = r.Where(c => c is RoundRockSymbol).Count();
+        return (index + 1) * numOfRoundRocks;
+      })
+      .Sum();
+  }
+
+  public static Dish Parse(string[] input)
+  {
+    var inputList = input
+      .Select(s => s.ToList())
+      .ToList();
+
+    return new Dish(inputList);
+  }
+}