Initial commit

2024/17/two_fixed.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+
+import sys
+
+input_file = sys.argv[1]
+
+with open(input_file) as fd:
+    lines = [line.rstrip() for line in fd.readlines()]
+
+original_B = int(lines[1].split(":")[1])
+original_C = int(lines[2].split(":")[1])
+program = [int(p) for p in lines[4].split(":")[1].split(",")]
+
+
+def output_given_A(A: int) -> list[int]:
+    instruction_pointer = 0
+    B = original_B
+    C = original_C
+
+    output: list[int] = list()
+
+    while instruction_pointer in range(len(program)):
+        instruction = program[instruction_pointer]
+        literal_operator = program[instruction_pointer + 1]
+
+        if instruction == 1:
+            B = B ^ literal_operator
+        elif instruction == 3:
+            if A != 0:
+                instruction_pointer = literal_operator
+                continue
+        elif instruction == 4:
+            B = B ^ C
+        else:
+            combined_operator = literal_operator
+            if literal_operator == 4:
+                combined_operator = A
+            elif literal_operator == 5:
+                combined_operator = B
+            elif literal_operator == 6:
+                combined_operator = C
+
+            if instruction == 2:
+                B = combined_operator % 8
+            elif instruction == 5:
+                output.append(combined_operator % 8)
+            else:
+                trunc_div = A >> combined_operator
+                if instruction == 0:
+                    A = trunc_div
+                elif instruction == 6:
+                    B = trunc_div
+                else:
+                    C = trunc_div
+        instruction_pointer += 2
+
+    return output
+
+
+def input_to_a(input_numbers: list[int]) -> int:
+    A = 0
+    for number in reversed(input_numbers):
+        A = (A << 3) + number
+    return A
+
+
+input_numbers: list[int] = program.copy()
+output_numbers: list[int] = output_given_A(input_to_a(input_numbers))
+while output_numbers != program:
+    for i in reversed(range(len(input_numbers))):
+        attempted_number = 0
+        while len(output_numbers) != len(program) or output_numbers[i] != program[i]:
+            input_numbers[i] = attempted_number
+            A = input_to_a(input_numbers)
+            output_numbers = output_given_A(A)
+            attempted_number += 1
+
+print(A)