Day 24

day24/part1.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+
+lines = (x.strip() for x in open("input.txt"))
+
+blacks = set()
+
+for line in lines:
+    x, y = 0, 0
+    while len(line):
+        if line[0] == "n":
+            y += 1
+            x += 1 if line[1] == "e" else 0
+            line = line[2:]
+        elif line[0] == "s":
+            y -= 1
+            x -= 1 if line[1] == "w" else 0
+            line = line[2:]
+        else:
+            x += 1 if line[0] == "e" else -1
+            line = line[1:]
+    if (x, y) in blacks:
+        blacks.discard((x, y))
+    else:
+        blacks.add((x, y))
+
+print(len(blacks))