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