Day 1

1 files changed, 39 insertions, 0 deletions

diff --git a/Day 1/Day_01.swift b/Day 1/Day_01.swift
new file mode 100755
index 0000000..b2a77f4
--- /dev/null
+++ b/Day 1/Day_01.swift
@@ -0,0 +1,39 @@
+#!/usr/bin/swift
+import Foundation
+
+guard CommandLine.arguments.count >= 2 else {
+    fatalError("Usage: ./Day_01 <input.txt>")
+}
+
+let moves = try! String(contentsOfFile: CommandLine.arguments[1], encoding: .utf8)
+    .split(separator: "\n")
+    .compactMap { line in
+        guard let first = line.first,
+              let magnitude = Int(line[line.index(after: line.startIndex)...])
+        else { fatalError("L13 : [ERROR] Failed to read magnitude error") }
+        let sign = (first == "R" ? 1 : -1)
+        return sign * magnitude
+    }
+
+var dialValue = 50
+var count = 0
+for move in moves {
+    dialValue = ((dialValue + move) % 100 + 100) % 100
+    if dialValue == 0 {
+        count += 1
+    }
+}
+print("=======Part 1=======\n\(count)")
+
+dialValue = 50
+count = 0
+for move in moves {
+    let magnitude = abs(move)
+    let effectivePosition = move > 0 ? dialValue : (100 - dialValue) % 100
+    count += (effectivePosition + magnitude - 1) / 100
+    dialValue = ((dialValue + move) % 100 + 100) % 100
+    if dialValue == 0 {
+        count += 1
+    }
+}
+print("=======Part 2=======\n\(count)")
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