1 files changed, 43 insertions, 0 deletions
diff --git a/Day01.cs b/Day01.cs
new file mode 100644
index 0000000..d991917
--- /dev/null
+++ b/Day01.cs
@@ -0,0 +1,43 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace aoc2019
+{
+    internal sealed class Day01 : Day
+    {
+        private readonly IEnumerable<int> masses;
+
+        public Day01() : base(1, "The Tyranny of the Rocket Equation")
+        {
+            masses = Input.Select(int.Parse);
+        }
+
+        private static int FuelCost(int weight)
+        {
+            return weight / 3 - 2;
+        }
+
+        private static int FullCost(int cost)
+        {
+            int total = 0, newcost, tmp = cost;
+
+            while ((newcost = FuelCost(tmp)) >= 0)
+            {
+                total += newcost;
+                tmp = newcost;
+            }
+
+            return total;
+        }
+
+        protected override string Part1()
+        {
+            return $"{masses.Sum(FuelCost)}";
+        }
+
+        protected override string Part2()
+        {
+            return $"{masses.Sum(FullCost)}";
+        }
+    }
+}
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