This day was pretty easy, though I made a stupid mistake and took too long. Also started way late. But only 13 lines total for part 2

day_18/part1.py

@@ -0,0 +1,31 @@
+import numpy as np
+
+def test(input, solution):
+    # print(f"Running input {input}")
+    result = process(input)
+    print(f"Solution was {result}")
+    assert result == solution
+
+def run():
+    file = open("input.txt", "r")
+    return process(file.read()[:-1])
+
+def process_line(line):
+    (direction, amount, _) = line.split()
+    return direction, int(amount)
+
+direction_map = {"L": (0,-1), "R": (0,1), "D": (-1,0), "U": (1,0)}
+
+def process(input):
+    points = []
+    perimeter_area = 0
+    current_point = (0,0)
+    for line in input.split("\n"):
+        (dir_letter, amount) = process_line(line)
+        direction = (direction_map[dir_letter][0] * amount, direction_map[dir_letter][1] * amount)
+        perimeter_area += amount
+        current_point = (current_point[0] + direction[0], current_point[1] + direction[1])
+        points.append(current_point)
+    indices = list(range(len(points) - 1)) + [-1]
+    determinants = [np.linalg.det(np.array([[points[i][1], points[i+1][1]],[points[i][0], points[i+1][0]]])) for i in indices]
+    return round(abs(sum(determinants))/2) + perimeter_area/2 + 1