solution for day 10

1 files changed, 34 insertions, 0 deletions

diff --git a/solutions/day10.fs b/solutions/day10.fs
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+namespace Solutions
+
+module Day10 =
+    open System.IO
+    open System.Text.RegularExpressions
+
+    let (|InstRegex|_|) pattern line =
+        let matched = Regex.Match(line, pattern)
+        if matched.Success then
+            matched.Groups |> Seq.tail |> Seq.map (fun x -> x.Value) |> List.ofSeq |> Some
+        else None
+
+    let parseInst line =
+        match line with
+        | InstRegex "noop" [] -> [0]
+        | InstRegex "addx (-?\d+)" x -> [0; (int x[0])]
+        | _ -> failwith "invalid input"
+
+    let changes = File.ReadLines("inputs/day10.txt") |> Seq.map parseInst |> List.concat
+
+    let executeInsts changes =
+        List.scan (+) 1 changes
+
+    let getStateSum cycles (states: int list) =
+        cycles |> List.map (fun x -> x * states[x-1]) |> List.sum
+
+    let part1 () = executeInsts changes |> getStateSum [20; 60; 100; 140; 180; 220]
+
+    let part2 () = executeInsts changes 
+                    |> List.mapi (fun pixel signal -> abs (signal - (pixel % 40)) <= 1) 
+                    |> List.map (fun x -> if x then "#" else " ")
+                    |> List.chunkBySize 40
+                    |> List.map (String.concat "")
+                    |> List.iter (printf "%s\n")
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