My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add solution for 2024/17
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2024/day17.py
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2024/day17.py
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import fileinput
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from utils import parse_nums
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def simulate(program, a, b, c):
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pc = 0
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out = []
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while pc < len(program):
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opcode, literal = program[pc:pc+2]
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if literal <= 3:
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combo = literal
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elif literal == 4:
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combo = a
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elif literal == 5:
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combo = b
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elif literal == 6:
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combo = c
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if opcode == 0:
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a = a // (2 ** combo)
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elif opcode == 1:
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b ^= literal
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elif opcode == 2:
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b = combo % 8
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elif opcode == 3:
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if a != 0:
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pc = literal * 2
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continue
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elif opcode == 4:
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b ^= c
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elif opcode == 5:
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out.append(combo % 8)
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elif opcode == 6:
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b = a // (2 ** combo)
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elif opcode == 7:
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c = a // (2 ** combo)
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pc += 2
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return out
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# Read problem input.
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for i, line in enumerate(fileinput.input()):
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if i == 0:
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A = parse_nums(line)[0]
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elif i == 1:
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B = parse_nums(line)[0]
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elif i == 2:
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C = parse_nums(line)[0]
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elif i == 4:
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PROGRAM = parse_nums(line)
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# Simulate the program for part 1.
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part_1 = simulate(PROGRAM, A, B, C)
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print("Part 1:", ','.join(str(n) for n in part_1))
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# Solve part 2.
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#
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# For the problem input, note that each "output byte" is affected
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# by a byte in order of the starting A register. You can manually
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# dial in some of the high bytes of the starting value to narrow
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# the search space until it's something viable to be simulated.
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start = 0o5322350130000000
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for s in range(start, start + 10000000):
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out = []
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A = s
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B = 0
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C = 0
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while True:
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B = A % 8
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B ^= 2
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C = (A // (2**B))
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A >>= 3
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B ^= C
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B ^= 7
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out.append(B % 8)
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if A == 0:
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break
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if out == PROGRAM:
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print("Part 2:", s)
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break