Continue with 2016 and 2017.

2016/d15.py

@@ -0,0 +1,45 @@
+import sys
+from lib import str_to_ints
+from copy import deepcopy
+
+with open("i15.txt") as f:
+    d = f.read()
+
+part_2 = True
+if part_2:
+    d += "#7 11 0  0"
+
+discs = []
+for line in d.splitlines():
+    id, npos, time, cpos = str_to_ints(line)
+    discs.append([cpos, npos])
+
+qpos = -1
+orig_discs = deepcopy(discs)
+
+# empirically could dev algo to find or CRT?
+if part_2:
+    start, delta = 12136, 33915
+else:
+    start, delta = 831, 2261
+
+for start_time in range(start, 1_000_000_000, delta):
+    discs = deepcopy(orig_discs)
+
+    # let discs move for initial wait
+    for _ in range(start_time):
+        for disc in discs:
+            disc[0] = (disc[0] + 1) % disc[1]
+
+    # drop the capsule 
+    for i in range(len(discs)):
+        # discs move first
+        for disc in discs:
+            disc[0] = (disc[0] + 1) % disc[1]
+
+        # check if there is a collission for the current disc
+        if discs[i][0] != 0:
+            break
+    else:
+        print(start_time)
+        sys.exit(0)