9-1

9/onestar.py

@@ -0,0 +1,41 @@
+seen = set()
+head = (0,0)
+tail = (0,0)
+
+direction = {
+    "R": (1, 0),
+    "L": (-1, 0),
+    "U": (0, 1),
+    "D": (0, -1)
+}
+
+def moveTail():
+    global tail
+    print(f"Calcing move for tail {tail} towards {head}")
+    if tail[0] == head[0] and abs(tail[1] - head[1]) > 1:
+        # Vertical move
+        tail = (tail[0], int((tail[1] + head[1]) / 2))
+    elif tail[1] == head[1] and abs(tail[0] - head[0]) > 1:
+        tail = (int((tail[0] + head[0]) / 2), tail[1])
+    elif abs(tail[0] - head[0]) <= 1 and abs(tail[1] - head[1]) <= 1:
+        # Touching diagonal, no action required
+        pass
+    else: 
+        # Non-touching diagonal, step required
+        dir = (min(1, max(-1, head[0] - tail[0])), min(1, max(-1, head[1] - tail[1])))
+        print(f"Moving in {dir}")
+        tail = (tail[0] + dir[0], tail[1] + dir[1])
+    print(tail)
+
+with open("input.txt", "r") as f:
+    for line in f.readlines():
+        line = line.strip()
+        [dir, steps] = line.split(" ")
+        for _ in range(int(steps)):
+            head = (head[0] + direction[dir][0], head[1] + direction[dir][1])
+            print(dir, head)
+            seen.add(tail)
+            moveTail()
+seen.add(tail)
+print(seen)
+print(len(seen))