[py] Port 2017_06

py/aoc/__init__.py

@@ -2,7 +2,7 @@ import sys
 import argparse
 from pathlib import Path
 
-from .y2017 import d01, d02, d03, d04, d05
+from .y2017 import d01, d02, d03, d04, d05, d06
 from .y2018 import d01, d02, d03, d04, d05, d06, d07, d08, d09, d10, d11
 from .y2020 import d10
 from .y2021 import d14
@@ -14,6 +14,7 @@ DAYS = {
     "2017_03": y2017.d03.solve,
     "2017_04": y2017.d04.solve,
     "2017_05": y2017.d05.solve,
+    "2017_06": y2017.d06.solve,
     "2018_01": y2018.d01.solve,
     "2018_02": y2018.d02.solve,
     "2018_03": y2018.d03.solve,

py/aoc/y2017/d06.py

@@ -0,0 +1,47 @@
+# PART 1
+
+
+def load_buckets(inputstr):
+    return tuple(map(int, inputstr[:-1].split("\t")))
+
+
+def redistribute(buckets):
+    l = list(buckets)
+    i = l.index(max(l))
+    n = l[i]
+    l[i] = 0
+
+    while n > 0:
+        i = (i + 1) % len(l)
+        l[i] += 1
+        n -= 1
+
+    return tuple(l)
+
+
+def find_repeat(buckets):
+    cycles = 0
+    states = {buckets: 0}
+    while True:
+        buckets = redistribute(buckets)
+        cycles += 1
+        if buckets in states:
+            return cycles, states[buckets]
+        else:
+            states[buckets] = cycles
+
+
+# PART 2
+
+
+def loop_cycles(buckets):
+    cycles, start_cycle = find_repeat(buckets)
+    return cycles - start_cycle
+
+
+def solve(inputstr):
+    buckets = load_buckets(inputstr)
+    cycles, _ = find_repeat(buckets)
+    print(f"Part 1: {cycles}")
+    cycles_2 = loop_cycles(buckets)
+    print(f"Part 2: {cycles_2}")