2024 day 17

Author: Peter554

2024/python/data/day17/example.txt

@@ -0,0 +1,5 @@
+Register A: 729
+Register B: 0
+Register C: 0
+
+Program: 0,1,5,4,3,0

2024/python/data/day17/input.txt

@@ -0,0 +1,5 @@
+Register A: 25986278
+Register B: 0
+Register C: 0
+
+Program: 2,4,1,4,7,5,4,1,1,4,5,5,0,3,3,0

2024/python/src/aoc2024/day17.py

@@ -0,0 +1,69 @@
+from pathlib import Path
+
+
+def part_1(input: Path) -> str:
+    lines = input.read_text().splitlines()
+    a = int(lines[0].split(":")[1].strip())
+    b = int(lines[1].split(":")[1].strip())
+    c = int(lines[2].split(":")[1].strip())
+    program = list(map(int, lines[4].split(":")[1].strip().split(",")))
+    return run_program(program, a, b, c)
+
+
+def run_program(program: list[int], a: int, b: int, c: int) -> str:
+    def literal(operand: int) -> int:
+        return operand
+
+    def combo(operand: int) -> int:
+        match operand:
+            case 0 | 1 | 2 | 3:
+                return operand
+            case 4:
+                return a
+            case 5:
+                return b
+            case 6:
+                return c
+            case _:
+                raise ValueError(f"Invalid combo operand: {operand}")
+
+    ip = 0
+    output: list[int] = []
+    while ip < len(program):
+        opcode = program[ip]
+        operand = program[ip + 1]
+        match opcode:
+            case 0:
+                numerator = a
+                denominator = 2 ** combo(operand)
+                a = numerator // denominator
+                ip += 2
+            case 1:
+                b = b ^ literal(operand)
+                ip += 2
+            case 2:
+                b = combo(operand) % 8
+                ip += 2
+            case 3:
+                if a == 0:
+                    ip += 2
+                else:
+                    ip = literal(operand)
+            case 4:
+                b = b ^ c
+                # operand unused.
+                ip += 2
+            case 5:
+                output.append(combo(operand) % 8)
+                ip += 2
+            case 6:
+                numerator = a
+                denominator = 2 ** combo(operand)
+                b = numerator // denominator
+                ip += 2
+            case 7:
+                numerator = a
+                denominator = 2 ** combo(operand)
+                c = numerator // denominator
+                ip += 2
+    return ",".join(map(str, output))

2024/python/tests/test_day17.py

@@ -0,0 +1,10 @@
+from pathlib import Path
+
+from aoc2024 import day17
+
+DATA_DIR = Path(__file__).parent.parent / "data/day17"
+
+
+def test_part_1():
+    assert day17.part_1(DATA_DIR / "example.txt") == "4,6,3,5,6,3,5,2,1,0"
+    assert day17.part_1(DATA_DIR / "input.txt") == "7,0,7,3,4,1,3,0,1"

README.md

@@ -5,7 +5,7 @@ https://adventofcode.com
 ## Progress
 
 <!-- PROGRESS_START -->
-Updated 2026-01-05.
+Updated 2026-01-06.
 
 | **Year**   | 🌟                | **1**   | **2**   | **3**   | **4**   | **5**   | **6**   | **7**   | **8**   | **9**   | **10**   | **11**   | **12**   | **13**   | **14**   | **15**   | **16**   | **17**   | **18**   | **19**   | **20**   | **21**   | **22**   | **23**   | **24**   | **25**   |
 |------------|------------------|---------|---------|---------|---------|---------|---------|---------|---------|---------|----------|----------|----------|----------|----------|----------|----------|----------|----------|----------|----------|----------|----------|----------|----------|----------|
@@ -18,8 +18,8 @@ Updated 2026-01-05.
 | **2021**   | **50/50**&nbsp;🌟 | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        |
 | **2022**   | **50/50**&nbsp;🌟 | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        |
 | **2023**   | 42/50            | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | ⬜        | 🟩        | ⬜        | ⬜        | ⬜        |
-| **2024**   | 32/50            | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | ⬜        | ⬜        | ⬜        | ⬜        | ⬜        | ⬜        | ⬜        | ⬜        | ⬜        |
+| **2024**   | 33/50            | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟩        | 🟨        | ⬜        | ⬜        | ⬜        | ⬜        | ⬜        | ⬜        | ⬜        | ⬜        |
 | **2025**   | **24/24**&nbsp;🌟 | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩       | 🟩        | 🟩        | 🟩        | ⬛        | ⬛        | ⬛        | ⬛        | ⬛        | ⬛        | ⬛        | ⬛        | ⬛        | ⬛        | ⬛        | ⬛        | ⬛        |
 
-Total stars: 346/524
+Total stars: 347/524
 <!-- PROGRESS_END -->