Add day 7

2025-01-24 10:19:11 +01:00
parent 9920041301
commit 9b865a12b1
4 changed files with 976 additions and 8 deletions
--- a/Days/Day7.cs
+++ b/Days/Day7.cs
@@ -0,0 +1,119 @@
+using Spectre.Console;
+
+namespace AdventOfCode.Days;
+
+public class Day7 : Day
+{
+    public override int Number => 7;
+    public override string Name => "Bridge Repair";
+
+    public override void RunPart1(bool display = true)
+    {
+        var calibrationResult = 0L;
+
+        foreach (var line in Input.AsSpan().EnumerateLines())
+        {
+            // Read input equation
+            var equationStart = line.IndexOf(':');
+
+            var target = long.Parse(line[..equationStart]);
+
+            var numbers = new List<long>();
+            var equationNumbers = line[(equationStart + 2)..];
+
+            foreach (var range in equationNumbers.Split(' '))
+            {
+                numbers.Add(int.Parse(equationNumbers[range]));
+            }
+
+            // Check if equation is possible
+            if (CheckEquation(target, numbers.ToArray().AsSpan()[1..], numbers[0]))
+            {
+                calibrationResult += target;
+            }
+        }
+
+        if (display)
+        {
+            AnsiConsole.MarkupLine($"[green]Total calibration result: [yellow]{calibrationResult}[/][/]");
+        }
+
+        return;
+
+        bool CheckEquation(long target, ReadOnlySpan<long> numbers, long result)
+        {
+            // Early return when result is greater than target because result is increasing
+            if (result > target)
+            {
+                return false;
+            }
+
+            if (numbers.IsEmpty)
+            {
+                return result == target;
+            }
+
+            var sumResult = result + numbers[0];
+            var multiplyResult = result * numbers[0];
+
+            return CheckEquation(target, numbers[1..], sumResult)
+                   || CheckEquation(target, numbers[1..], multiplyResult);
+        }
+    }
+
+    public override void RunPart2(bool display = true)
+    {
+        var calibrationResult = 0L;
+
+        foreach (var line in Input.AsSpan().EnumerateLines())
+        {
+            // Read input equation
+            var equationStart = line.IndexOf(':');
+
+            var target = long.Parse(line[..equationStart]);
+
+            var numbers = new List<long>();
+            var equationNumbers = line[(equationStart + 2)..];
+
+            foreach (var range in equationNumbers.Split(' '))
+            {
+                numbers.Add(int.Parse(equationNumbers[range]));
+            }
+
+            // Check if equation is possible
+            if (CheckEquation(target, numbers.ToArray().AsSpan()[1..], numbers[0]))
+            {
+                calibrationResult += target;
+            }
+        }
+
+        if (display)
+        {
+            AnsiConsole.MarkupLine($"[green]Total calibration result: [yellow]{calibrationResult}[/][/]");
+        }
+
+        return;
+
+        bool CheckEquation(long target, ReadOnlySpan<long> numbers, long result)
+        {
+            // Early return when result is greater than target because result is increasing
+            if (result > target)
+            {
+                return false;
+            }
+
+            if (numbers.IsEmpty)
+            {
+                return result == target;
+            }
+
+            var sumResult = result + numbers[0];
+            var multiplyResult = result * numbers[0];
+            var concatResult = result * (int)Math.Pow(10, (int)Math.Log10(numbers[0]) + 1) + numbers[0];
+
+            return CheckEquation(target, numbers[1..], sumResult)
+                   || CheckEquation(target, numbers[1..], multiplyResult)
+                   || CheckEquation(target, numbers[1..], concatResult);
+        }
+    }
+}