diff options
| -rw-r--r-- | aoc2021.test/DayTests.cs | 2 | ||||
| -rw-r--r-- | aoc2021/Day03.cs | 23 |
2 files changed, 23 insertions, 2 deletions
diff --git a/aoc2021.test/DayTests.cs b/aoc2021.test/DayTests.cs index f9d2a1d..df97b57 100644 --- a/aoc2021.test/DayTests.cs +++ b/aoc2021.test/DayTests.cs @@ -6,7 +6,7 @@ public class DayTests [DataTestMethod] [DataRow(typeof(Day01), "1616", "1645")] [DataRow(typeof(Day02), "2272262", "2134882034")] - [DataRow(typeof(Day03), "3009600", "")] + [DataRow(typeof(Day03), "3009600", "6940518")] public void CheckAllDays(Type dayType, string part1, string part2) { var s = Stopwatch.StartNew(); diff --git a/aoc2021/Day03.cs b/aoc2021/Day03.cs index a9e5c38..e1003c4 100644 --- a/aoc2021/Day03.cs +++ b/aoc2021/Day03.cs @@ -33,6 +33,27 @@ public sealed class Day03 : Day public override string Part2() { - return ""; + var o = _report; + var c = _report; + + var i = 0; + while (o.Count > 1) + { + var most = o.Count(r => r[i] == '1') >= o.Count / 2.0 ? '1' : '0'; + o = o.Where(r => r[i] == most).ToList(); + i++; + } + var o2 = Convert.ToInt64(o.Single(), 2); + + i = 0; + while (c.Count > 1) + { + var most = c.Count(r => r[i] == '1') >= c.Count / 2.0 ? '0' : '1'; + c = c.Where(r => r[i] == most).ToList(); + i++; + } + var co2 = Convert.ToInt64(c.Single(), 2); + + return $"{o2 * co2}"; } } |