2019: d01: ex2: add solution

2019/d01/ex2/ex2.py

@@ -0,0 +1,15 @@
+#!/usr/bin/env python
+import sys
+
+
+def calc_fuel(mass: int) -> int:
+    fuel = mass // 3 - 2
+    return fuel + calc_fuel(fuel) if fuel > 0 else 0
+
+
+def main() -> None:
+    print(sum(calc_fuel(int(l)) for l in sys.stdin))
+
+
+if __name__ == "__main__":
+    main()