Day 09

day08/part2.py

@@ -20,7 +20,7 @@ for y in range(len(forest)):
                 pos += dir
             score *= dir_score
         max_score = max(max_score, score)
-        print(max_score)
+print(max_score)
 
 
 

day09/part1.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+import numpy as np
+
+lines = (x.strip() for x in open("input.txt"))
+positions = set()
+LEN = 2
+rope = [np.array((0, 0)) for i in range(LEN)]
+dirs = {
+    "U": np.array((1, 0)),
+    "D": np.array((-1, 0)),
+    "L": np.array((0, -1)),
+    "R": np.array((0, 1)),
+}
+
+for line in lines:
+    d, i = line.split(" ")
+    d, i = dirs[d], int(i)
+    for _ in range(i):
+        rope[0] += d
+        for p in range(1, 2):
+            diff = rope[p-1]-rope[p]
+            rope[p] += np.sign(diff) if sum(np.abs(diff)) > 2 else np.sign(diff-np.sign(diff))
+        positions.add(tuple(rope[len(rope)-1]))
+
+print(len(positions))

day09/part2.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+import numpy as np
+
+lines = (x.strip() for x in open("input.txt"))
+positions = set()
+rope = [np.array((0, 0)) for _ in range(10)]
+dirs = {d: p for d, p in zip("UDLR", ((1, 0), (-1, 0), (0, -1), (0, 1)))}
+
+for line in lines:
+    d, n = dirs[line[0]], int(line[2:])
+    for _ in range(n):
+        rope[0] += d
+        for i in range(1, len(rope)):
+            diff = rope[i-1] - rope[i]
+            rope[i] += np.sign(diff) if sum(np.abs(diff)) > 2 else np.sign(diff - np.sign(diff))
+        positions.add(tuple(rope[len(rope)-1]))
+
+print(len(positions))