Update readme and lib and start 2015.

2015/d3.py

@@ -0,0 +1,41 @@
+import sys
+from lib import *
+
+data = open(0).read()
+
+part_1 = False
+
+DIRS = {
+    "^": (-1, 0),
+    ">": (0, 1),
+    "v": (1, 0),
+    "<": (0, -1),
+}
+
+if part_1:
+    pos = (0, 0)
+    poss = set([pos])
+
+    for c in data:
+        d = DIRS[c]
+        pos = pos[0] + d[0], pos[1] + d[1]
+        poss.add(pos)
+
+    print(len(poss))
+    sys.exit(0)
+
+a = (0, 0)
+b = (0, 0)
+poss = set([a, b])
+for i, c in enumerate(data):
+    if i % 2 == 0:
+        d = DIRS[c]
+        a = a[0] + d[0], a[1] + d[1]
+        poss.add(a)
+    else:
+        d = DIRS[c]
+        b = b[0] + d[0], b[1] + d[1]
+        poss.add(b)
+
+print(len(poss))
+sys.exit(0)