advent-of-code/2019/day2/day2.py

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2024-12-03 14:26:47 +00:00
def interpret_intcode(input_prog):
# Instruction pointer: index of the next element to be executed
ip = 0
while ip < len(input_prog):
instruction = input_prog[ip]
if instruction == 99:
break
elif instruction == 1:
# The operands to sum are at the memory location ip+1 and ip+2.
operands = (input_prog[input_prog[ip + 1]], input_prog[input_prog[ip + 2]])
result = sum(operands)
target = input_prog[ip + 3]
input_prog[target] = result
ip += 4
elif instruction == 2:
# The operands to multiply are at the memory location ip+1 and ip+2.
operands = (input_prog[input_prog[ip + 1]], input_prog[input_prog[ip + 2]])
result = operands[0] * operands[1]
target = input_prog[ip + 3]
input_prog[target] = result
ip += 4
def tests():
inputs = (
[1, 0, 0, 0, 99], # ADD 1 + 1 to location 0
[2, 3, 0, 3, 99], # MUL 2 * 3 to location 3
[2, 4, 4, 5, 99, 0],
[1, 1, 1, 4, 99, 5, 6, 0, 99],
)
expected_outputs = (
[2, 0, 0, 0, 99], # 1 + 1 = 2
[2, 3, 0, 6, 99], # 3 * 2 = 6
[2, 4, 4, 5, 99, 9801], # 99 * 99 = 9801
[30, 1, 1, 4, 2, 5, 6, 0, 99],
)
for i, inp in enumerate(inputs):
result = inp[:]
interpret_intcode(result)
assert (
result == expected_outputs[i]
), f"Expected output for {inp} is {expected_outputs[i]}, but found {result} instead."
print("All tests passed.")
def run_program(memory, noun, verb):
memory[1] = noun
memory[2] = verb
interpret_intcode(memory)
return memory[0]
if __name__ == "__main__":
tests()
with open("input.txt") as inp:
memory = [int(x) for x in inp.readline().strip().split(",")]
# Pass a copy to avoid modifying the original memory
print("Part 1 answer: ", run_program(memory[:], 12, 2))
# Part 2
result = 0
for verb in range(99):
for noun in range(99):
if run_program(memory[:], noun, verb) == 19690720:
print(f"Part 2: noun={noun}, verb={verb}")
print("Result = ", 100 * noun + verb)
break