From 69ba3abc1f60b8756f68fac570ecda31a2086325 Mon Sep 17 00:00:00 2001
From: Nat Lasseter <user@4574.co.uk>
Date: Wed, 6 Dec 2023 12:28:22 +0000
Subject: Day 06

---
 day06/day06.java | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 day06/input      |  2 ++
 day06/test       |  2 ++
 3 files changed, 63 insertions(+)
 create mode 100644 day06/day06.java
 create mode 100644 day06/input
 create mode 100644 day06/test

diff --git a/day06/day06.java b/day06/day06.java
new file mode 100644
index 0000000..4965501
--- /dev/null
+++ b/day06/day06.java
@@ -0,0 +1,59 @@
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.util.ArrayList;
+import java.util.regex.Pattern;
+import java.util.regex.Matcher;
+
+public class day06 {
+  public static void main(String args[]) throws IOException {
+    RandomAccessFile input = new RandomAccessFile("input", "r");
+    System.out.println("Day 06 Part 1: " + part1(input));
+    input.seek(0);
+    System.out.println("Day 06 Part 2: " + part2(input));
+    input.close();
+  }
+
+  public static String part1(RandomAccessFile input) throws IOException {
+    ArrayList<Integer[]> races = new ArrayList<>();
+    Pattern digits = Pattern.compile("\\d+");
+    Matcher times = digits.matcher(input.readLine());
+    Matcher distances = digits.matcher(input.readLine());
+
+    while (times.find()) {
+      distances.find();
+      races.add(new Integer[]{
+        Integer.parseInt(times.group()),
+        Integer.parseInt(distances.group())
+      });
+    }
+
+    int margin = 1;
+    for (Integer[] race: races) {
+      int wins = 0;
+      for (int hold = 1; hold < race[0]; hold++) {
+        int dist = (race[0] - hold) * hold;
+        if (dist > race[1]) {
+          wins += 1;
+        }
+      }
+      margin *= wins;
+    }
+
+    return Integer.toString(margin);
+  }
+
+  public static String part2(RandomAccessFile input) throws IOException {
+    long time = Long.parseLong(input.readLine().replaceAll(" ", "").substring(5));
+    long distance = Long.parseLong(input.readLine().replaceAll(" ", "").substring(9));
+
+    int wins = 0;
+    for (long hold = 1; hold < time; hold++) {
+      long dist = (time - hold) * hold;
+      if (dist > distance) {
+        wins += 1;
+      }
+    }
+
+    return Integer.toString(wins);
+  }
+}
diff --git a/day06/input b/day06/input
new file mode 100644
index 0000000..7c06e07
--- /dev/null
+++ b/day06/input
@@ -0,0 +1,2 @@
+Time:        59     68     82     74
+Distance:   543   1020   1664   1022
diff --git a/day06/test b/day06/test
new file mode 100644
index 0000000..28f5ae9
--- /dev/null
+++ b/day06/test
@@ -0,0 +1,2 @@
+Time:      7  15   30
+Distance:  9  40  200
-- 
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