Day 06

day06.groovy

@@ -0,0 +1,70 @@
+import groovy.transform.TupleConstructor;
+import groovy.transform.ToString;
+
+
+def input = new File("input/day06.txt")
+    .readLines()
+
+def times = input[0].split(/:\W+/)[1].split(/\W+/).collect { it.toLong() };
+def distances = input[1].split(/:\W+/)[1].split(/\W+/).collect { it.toLong() };
+
+@TupleConstructor
+@ToString
+class Race {
+    long time;
+    long distance;
+
+    long play(long holdingButtonTime) {
+        long speed = holdingButtonTime;
+        long timeRemaining = time - holdingButtonTime;
+        return timeRemaining * speed;
+    }
+}
+
+{
+    assert new Race(7, 9).play(0) == 0
+    assert new Race(7, 9).play(1) == 6
+    assert new Race(7, 9).play(2) == 10
+    assert new Race(7, 9).play(3) == 12
+    assert new Race(7, 9).play(4) == 12
+    assert new Race(7, 9).play(5) == 10
+    assert new Race(7, 9).play(6) == 6
+    assert new Race(7, 9).play(7) == 0
+}
+
+def races = (0..<times.size()).collect { i -> 
+    new Race(times[i], distances[i]);
+}
+
+
+println races.collect { race ->
+    def results = (0..<(race.time)).collect { i ->
+        return [i, race.play(i)]
+    }.findAll { it[1] > race.distance }
+
+    return results.size();
+}.inject(1) { acc, it -> acc * it };
+
+
+def finalRace = new Race(
+    input[0].split(/:\W+/)[1].split(/\W+/).join("").toLong(),
+    input[1].split(/:\W+/)[1].split(/\W+/).join("").toLong()
+);
+
+def count = 0;
+def prev = null;
+for (int i = 0; i < finalRace.time; i++) {
+    def curr = finalRace.play(i);
+
+    if (curr > finalRace.distance) {
+        count += 1;
+    }
+
+    if (prev != null && curr < finalRace.distance && i > finalRace.time / 2) {
+        break;
+    }
+
+    prev = curr
+}
+
+println(count);

input/day06.txt

@@ -0,0 +1,2 @@
+Time:        51     92     68     90
+Distance:   222   2031   1126   1225