-
Notifications
You must be signed in to change notification settings - Fork 0
/
8.py
99 lines (74 loc) · 2.65 KB
/
8.py
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
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
# Data
with open("./input/input_8.txt", 'r') as f:
data = f.read().splitlines()
# format the data into a list which contains
# instructions of the form ['instruction', offset]
data = [(lambda x: [x[0], int(x[1])])(instruction.split(' '))
for instruction in data]
def run_boot_code(data, change_instruction_idx=None):
"""
Function to process boot code instructions
Input:
data (list): List of instructions
change_instruction_idx (int): Index value of instruction to
change from nop to jmp or vice versa. default value: None
Returns:
non_halting_loop (bool): Flag to indicate presence of
non-halting loop in the code
accumulator (int): Last updated value of accumulator
"""
accumulator = 0
visited_instructions = []
non_halting_loop = bool()
current_instruction_idx = 0
while not non_halting_loop and current_instruction_idx < len(data):
# check for non halting loop
if (current_instruction_idx) in visited_instructions:
non_halting_loop = True
break
visited_instructions.append(current_instruction_idx)
instruction, arg_value = data[current_instruction_idx]
# check if current instruction needs to be changed
# jmp to nop or nop to jmp
if current_instruction_idx == change_instruction_idx:
if instruction == 'jmp':
instruction = 'nop'
elif instruction == 'nop':
instruction = 'jmp'
# process instruction
if instruction == 'jmp':
current_instruction_idx += arg_value
continue
elif instruction == 'acc':
accumulator += arg_value
# go to the next instruction
current_instruction_idx += 1
return non_halting_loop, accumulator
# Part 1
non_halting_loop, accumulator = run_boot_code(data)
# Output answer
print("Part 1")
if non_halting_loop:
print("Non-halting loop detected")
print("Value of accumulator: {}\n".format(accumulator))
else:
print("Boot code executed successfully\n")
# Part 2
# list of indices of jmp and nop instructions
change_idx = list()
for idx in range(len(data)):
if data[idx][0] == 'jmp' or data[idx][1] == 'nop':
change_idx.append(idx)
non_halting_loop, accumulator = True, None
for idx in change_idx:
non_halting_loop, accumulator = run_boot_code(
data, change_instruction_idx=idx)
if not non_halting_loop:
break
# Print answer
print("Part 2")
if non_halting_loop:
print("Non-halting loop detected")
else:
print("Boot code executed successfully")
print("Value of accumulator: {}\n".format(accumulator))