Solution to problem 13 in Python

src/P13.py

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+# --- Day 13: Shuttle Search ---
+
+# Your ferry can make it safely to a nearby port, but it won't get much
+# further. When you call to book another ship, you discover that no ships
+# embark from that port to your vacation island. You'll need to get from the
+# port to the nearest airport.
+
+# Fortunately, a shuttle bus service is available to bring you from the sea
+# port to the airport! Each bus has an ID number that also indicates how often
+# the bus leaves for the airport.
+
+# Bus schedules are defined based on a timestamp that measures the number of
+# minutes since some fixed reference point in the past. At timestamp 0, every
+# bus simultaneously departed from the sea port. After that, each bus travels
+# to the airport, then various other locations, and finally returns to the sea
+# port to repeat its journey forever.
+
+# The time this loop takes a particular bus is also its ID number: the bus with
+# ID 5 departs from the sea port at timestamps 0, 5, 10, 15, and so on. The bus
+# with ID 11 departs at 0, 11, 22, 33, and so on. If you are there when the bus
+# departs, you can ride that bus to the airport!
+
+# Your notes (your puzzle input) consist of two lines. The first line is your
+# estimate of the earliest timestamp you could depart on a bus. The second line
+# lists the bus IDs that are in service according to the shuttle company;
+# entries that show x must be out of service, so you decide to ignore them.
+
+# To save time once you arrive, your goal is to figure out the earliest bus you
+# can take to the airport. (There will be exactly one such bus.)
+
+# For example, suppose you have the following notes:
+
+# 939
+# 7,13,x,x,59,x,31,19
+
+# Here, the earliest timestamp you could depart is 939, and the bus IDs in
+# service are 7, 13, 59, 31, and 19. Near timestamp 939, these bus IDs depart
+# at the times marked D:
+
+# time   bus 7   bus 13  bus 59  bus 31  bus 19
+# 929      .       .       .       .       .
+# 930      .       .       .       D       .
+# 931      D       .       .       .       D
+# 932      .       .       .       .       .
+# 933      .       .       .       .       .
+# 934      .       .       .       .       .
+# 935      .       .       .       .       .
+# 936      .       D       .       .       .
+# 937      .       .       .       .       .
+# 938      D       .       .       .       .
+# 939      .       .       .       .       .
+# 940      .       .       .       .       .
+# 941      .       .       .       .       .
+# 942      .       .       .       .       .
+# 943      .       .       .       .       .
+# 944      .       .       D       .       .
+# 945      D       .       .       .       .
+# 946      .       .       .       .       .
+# 947      .       .       .       .       .
+# 948      .       .       .       .       .
+# 949      .       D       .       .       .
+
+# The earliest bus you could take is bus ID 59. It doesn't depart until
+# timestamp 944, so you would need to wait 944 - 939 = 5 minutes before it
+# departs. Multiplying the bus ID by the number of minutes you'd need to wait
+# gives 295.
+
+# What is the ID of the earliest bus you can take to the airport multiplied by
+# the number of minutes you'll need to wait for that bus?
+
+from copy import copy
+
+with open("files/P13.txt", "r") as f:
+    start = int(f.readline())
+    buses = [int(bus) for bus in f.readline().strip().split(",") if bus != "x"]
+
+
+def part_1() -> None:
+    wait = copy(start)
+    found = False
+    while not found:
+        for bus in buses:
+            if wait % bus == 0:
+                print(f"Solution to part 1 is {str((wait - start) * bus)}")
+                found = True
+                break
+            wait += 1
+
+
+if __name__ == "__main__":
+    part_1()