84 lines
2.3 KiB
Python
84 lines
2.3 KiB
Python
def read_file():
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with open("input.txt","r") as f:
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return f.read().split('\n')
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def process(instructions):
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mask = "X"*36
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memory = {}
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for instruction in instructions:
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if instruction[0:4] == "mask":
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mask = instruction[7:] # trim "mask = "
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else:
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address = instruction[4:].split(']')[0] # trim "mem[", then split off everyting after "]"
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value = instruction.split('=')[1][1:] # split, take the second half, and trim the space
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value = str(format(int(value),'036b')) # 36 bits of binary, with leading 0s
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result = ""
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for m, b in zip(mask, value):
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if m == "0" or m == "1": # mask is applied
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result += m # so rewrite with mask bit
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else: # m == "X"
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result += b # so keep value bit
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memory[address] = result
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return memory
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def part1(instructions):
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memory = process(instructions)
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result = 0
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for address in memory:
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result += int(memory[address],2)
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return result
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def addresses(address, mask):
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addresses = []
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# TODO: learn how to use itertools to avoid having to manually do this stuff? bc "there must be a better way" ~raymond hettinger
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temp = ""
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for i in range(len(mask)):
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if mask[i] == "0":
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temp += address[i]
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elif mask[i] == "1":
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temp += mask[i]
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else: # mask[i] == "X"
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temp += "X"
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addresses.append(temp)
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iterations = mask.count("X")
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for i in range(iterations): # replace each X one by one
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a0s = []
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a1s = []
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for a in addresses:
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a0 = a.replace("X","0",1) # replace first X with 0
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a1 = a.replace("X","1",1) # replace first X with 1
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a0s.append(a0)
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a1s.append(a1)
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addresses = a0s + a1s # repopulate list -- should double in size
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return addresses
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def process2(instructions):
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mask = "0"*36
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memory = {}
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for instruction in instructions:
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if instruction[0:4] == "mask":
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mask = instruction[7:]
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else:
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address = instruction[4:].split(']')[0]
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address = str(format(int(address),'036b'))
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value = instruction.split('=')[1][1:]
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value = str(format(int(value),'036b'))
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exploded_addrs = addresses(address, mask) # explode mask due to quantum bits
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for address in exploded_addrs:
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memory[address] = value
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return memory
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def part2(instructions):
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memory = process2(instructions)
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result = 0
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for address in memory:
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result += int(memory[address],2)
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return result
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def main():
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instructions = read_file()
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print(part1(instructions), part2(instructions))
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if __name__ == "__main__":
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main() |