From 18351f93ebe3b080ba651bab5fc048ad46b394b8 Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Sat, 23 Jan 2021 21:33:10 +0100
Subject: [PATCH] Implement 2019 day 7

---
 2019/aoc2019/day07.py                      | 69 ++++++++++++++++++++++
 2019/tests/{test_day6.py => test_day06.py} |  0
 2019/tests/test_day07.py                   | 27 +++++++++
 3 files changed, 96 insertions(+)
 create mode 100644 2019/aoc2019/day07.py
 rename 2019/tests/{test_day6.py => test_day06.py} (100%)
 create mode 100644 2019/tests/test_day07.py

diff --git a/2019/aoc2019/day07.py b/2019/aoc2019/day07.py
new file mode 100644
index 0000000..b923273
--- /dev/null
+++ b/2019/aoc2019/day07.py
@@ -0,0 +1,69 @@
+import itertools
+from typing import List, TextIO, Tuple
+
+from aoc2019.intcode import read_program, Computer
+
+
+def amplify(phases: Tuple[int], program: List[int]) -> int:
+    amps = []
+
+    for i, phase in enumerate(phases):
+        amp = Computer(program.copy())
+
+        if i > 0:
+            amp.input = amps[i - 1].output
+
+        amp.input.append(phase)
+
+        amps.append(amp)
+
+    amps[0].input.append(0)
+
+    for amp in amps:
+        amp.run()
+
+    return amps[-1].output.pop()
+
+
+def reamplify(phases: Tuple[int], program: List[int]) -> int:
+    amps = []
+
+    for i, _ in enumerate(phases):
+        amp = Computer(program.copy())
+
+        if i > 0:
+            amp.input = amps[i - 1].output
+
+        amps.append(amp)
+
+    amps[0].input = amps[-1].output
+
+    for amp, phase in zip(amps, phases):
+        amp.input.append(phase)
+
+    amps[0].input.append(0)
+
+    changes = True
+
+    while changes:
+        changes = False
+        for amp in amps:
+            try:
+                amp.run()
+            except IndexError:
+                # Waiting for input
+                changes = True
+
+    return amps[-1].output.pop()
+
+
+def part1(data: TextIO) -> int:
+    program = read_program(data)
+
+    return max(amplify(phase, program) for phase in itertools.permutations(range(0, 5)))
+
+
+def part2(data: TextIO) -> int:
+    program = read_program(data)
+
+    return max(reamplify(phase, program) for phase in itertools.permutations(range(5, 10)))
diff --git a/2019/tests/test_day6.py b/2019/tests/test_day06.py
similarity index 100%
rename from 2019/tests/test_day6.py
rename to 2019/tests/test_day06.py
diff --git a/2019/tests/test_day07.py b/2019/tests/test_day07.py
new file mode 100644
index 0000000..76af1c7
--- /dev/null
+++ b/2019/tests/test_day07.py
@@ -0,0 +1,27 @@
+from io import StringIO
+
+import pytest
+
+from aoc2019.day07 import part1, part2
+
+
+@pytest.mark.parametrize('maximum,program', [
+    (43210, "3,15,3,16,1002,16,10,16,1,16,15,15,4,15,99,0,0"),
+    (54321, "3,23,3,24,1002,24,10,24,1002,23,-1,23,101,5,23,23,1,24,23,23,4,23,99,0,0"),
+    (65210, "3,31,3,32,1002,32,10,32,1001,31,-2,31,1007,31,0,33,1002,33,7,33,1,33,31,31,1,32,31,31,4,31,99,0,0,0"),
+])
+def test_sample_part1(maximum: int, program: str) -> None:
+    data = StringIO(program)
+
+    assert part1(data) == maximum
+
+
+@pytest.mark.parametrize('maximum,program', [
+    (139629729, "3,26,1001,26,-4,26,3,27,1002,27,2,27,1,27,26,27,4,27,1001,28,-1,28,1005,28,6,99,0,0,5"),
+    (18216, "3,52,1001,52,-5,52,3,53,1,52,56,54,1007,54,5,55,1005,55,26,1001,54,-5,54,1105,1,12,1,53,54,"
+            "53,1008,54,0,55,1001,55,1,55,2,53,55,53,4,53,1001,56,-1,56,1005,56,6,99,0,0,0,0,10"),
+])
+def test_sample_part2(maximum: int, program: str) -> None:
+    data = StringIO(program)
+
+    assert part2(data) == maximum