From f41c4cd0980b6ce21ac7cb12feba6d6ffd9d8358 Mon Sep 17 00:00:00 2001
From: Gabriel Augendre <gabriel@augendre.info>
Date: Mon, 6 Dec 2021 13:57:04 +0100
Subject: [PATCH] Solve day 6

---
 2021/day06_lanternfish.py | 56 +++++++++++++++++++++++++++++++++++++++
 2021/inputs/day06         |  1 +
 2021/inputs/day06-test1   |  1 +
 3 files changed, 58 insertions(+)
 create mode 100644 2021/day06_lanternfish.py
 create mode 100644 2021/inputs/day06
 create mode 100644 2021/inputs/day06-test1

diff --git a/2021/day06_lanternfish.py b/2021/day06_lanternfish.py
new file mode 100644
index 0000000..8022efe
--- /dev/null
+++ b/2021/day06_lanternfish.py
@@ -0,0 +1,56 @@
+from collections import defaultdict
+from concurrent.futures import ThreadPoolExecutor, as_completed
+from typing import Dict, Iterator, List
+
+
+def main(filename: str, expected_part_1: int = None, expected_part_2: int = None):
+    print(f"\n+ Running on {filename}")
+    with open(filename) as f:
+        data = f.read().strip().split("\n")
+
+    data = parse_data(data)
+    solution_part_1 = solve_part_1(data)
+
+    print(f"1. Found {solution_part_1}")
+    if expected_part_1:
+        assert expected_part_1 == solution_part_1
+
+    solution_part_2 = solve_part_2(data)
+    print(f"2. Found {solution_part_2}")
+    if expected_part_2:
+        assert expected_part_2 == solution_part_2
+
+
+def parse_data(data: List[str]) -> Dict[int, int]:
+    dct = defaultdict(int)
+    for x in map(int, data[0].split(",")):
+        dct[x] += 1
+    return dct
+
+
+def solve_part_1(data) -> int:
+    for _ in range(80):
+        data = _run_day(data)
+    return sum(data.values())
+
+
+def _run_day(data: Dict[int, int]) -> Dict[int, int]:
+    new_data = defaultdict(int)
+    for k, v in data.items():
+        if k == 0:
+            new_data[6] += v
+            new_data[8] += v
+        else:
+            new_data[k - 1] += v
+    return new_data
+
+
+def solve_part_2(data) -> int:
+    for _ in range(256):
+        data = _run_day(data)
+    return sum(data.values())
+
+
+if __name__ == "__main__":
+    main("inputs/day06-test1", expected_part_1=5934, expected_part_2=26984457539)
+    main("inputs/day06", expected_part_1=345793)
diff --git a/2021/inputs/day06 b/2021/inputs/day06
new file mode 100644
index 0000000..3d35529
--- /dev/null
+++ b/2021/inputs/day06
@@ -0,0 +1 @@
+3,1,5,4,4,4,5,3,4,4,1,4,2,3,1,3,3,2,3,2,5,1,1,4,4,3,2,4,2,4,1,5,3,3,2,2,2,5,5,1,3,4,5,1,5,5,1,1,1,4,3,2,3,3,3,4,4,4,5,5,1,3,3,5,4,5,5,5,1,1,2,4,3,4,5,4,5,2,2,3,5,2,1,2,4,3,5,1,3,1,4,4,1,3,2,3,2,4,5,2,4,1,4,3,1,3,1,5,1,3,5,4,3,1,5,3,3,5,4,2,3,4,1,2,1,1,4,4,4,3,1,1,1,1,1,4,2,5,1,1,2,1,5,3,4,1,5,4,1,3,3,1,4,4,5,3,1,1,3,3,3,1,1,5,4,2,5,1,1,5,5,1,4,2,2,5,3,1,1,3,3,5,3,3,2,4,3,2,5,2,5,4,5,4,3,2,4,3,5,1,2,2,4,3,1,5,5,1,3,1,3,2,2,4,5,4,2,3,2,3,4,1,3,4,2,5,4,4,2,2,1,4,1,5,1,5,4,3,3,3,3,3,5,2,1,5,5,3,5,2,1,1,4,2,2,5,1,4,3,3,4,4,2,3,2,1,3,1,5,2,1,5,1,3,1,4,2,4,5,1,4,5,5,3,5,1,5,4,1,3,4,1,1,4,5,5,2,1,3,3
diff --git a/2021/inputs/day06-test1 b/2021/inputs/day06-test1
new file mode 100644
index 0000000..a7af2b1
--- /dev/null
+++ b/2021/inputs/day06-test1
@@ -0,0 +1 @@
+3,4,3,1,2
\ No newline at end of file