"""
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Advent of Code 2021 - Day 03
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Run with:
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python puzzles/day03.py inputs/day03.txt
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"""
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import pathlib
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import sys
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from typing import Dict, List, Tuple
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from collections import defaultdict
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class Diagnostics:
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report = None
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def __init__(self, report: List[int]) -> None:
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self.report = report
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def calc_power_usage(self) -> int:
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most_common = self.commonality(self.report)
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gamma = epsilon = ""
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for common in most_common:
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if common == 1:
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gamma += "1"
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epsilon += "0"
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else:
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gamma += "0"
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epsilon += "1"
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gamma = int(gamma, 2)
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epsilon = int(epsilon, 2)
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return gamma * epsilon
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def calc_life_support_rating(self) -> int:
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oxygen_generator_rating = self.calc_oxygen_generator_rating(self.report)
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co2_scrubber_rating = self.calc_co2_scrubber_rating(self.report)
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return oxygen_generator_rating * co2_scrubber_rating
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def calc_oxygen_generator_rating(self, inputs: List[str]) -> int:
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"""
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Bit Criteria:
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Most common value in current bit position
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If 0 and 1 are equally common, keep values with a 1
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Keep only values with this bit in this position
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"""
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report = inputs.copy()
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for column in range(len(report[0])):
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most_common = self.commonality(report)
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for binary in list(report):
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if (
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int(binary[column]) != most_common[column]
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and most_common[column] != 2
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) or (most_common[column] == 2 and binary[column] != "1"):
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report.remove(binary)
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if len(report) == 1:
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return int(report[0], 2)
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return int(report[0], 2)
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def calc_co2_scrubber_rating(self, inputs: List[str]) -> int:
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"""
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Bit Criteria:
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Least common value in current position
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If 0 and 1 are equally common, keep values with a 0
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Keep only values with this bit in this position
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"""
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report = inputs.copy()
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for column in range(len(report[0])):
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most_common = self.commonality(report)
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for binary in list(report):
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if (int(binary[column]) == most_common[column]) or (
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most_common[column] == 2 and binary[column] != "0"
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):
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report.remove(binary)
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if len(report) == 1:
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return int(report[0], 2)
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return int(report[0], 2)
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@staticmethod
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def commonality(report: List[str]) -> List[int]:
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"""
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Return the most common value in each column of binary numbers
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Args:
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report: List of binary numbers
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Returns:
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List containing the most common value in the column
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Possible Values:
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0
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1
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2 - This indicates equally common
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"""
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num_1 = defaultdict(int)
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for binary in report:
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for column, bit in enumerate(binary):
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num_1[column] += int(bit)
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common = []
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half_total = len(report) / 2
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for count in num_1.values():
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if count == half_total:
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common.append(2) # Indicating equally common
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elif count > half_total:
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common.append(1)
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else:
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common.append(0)
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return common
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def part1(inputs: List[int]) -> int:
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diag = Diagnostics(inputs)
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return diag.calc_power_usage()
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def part2(inputs: List[int]) -> int:
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diag = Diagnostics(inputs)
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return diag.calc_life_support_rating()
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def parse(inputs: str) -> List[int]:
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"""Parse the input string"""
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return [line for line in inputs.split()]
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def solve(path: str) -> Tuple[int, int]:
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"""Solve the puzzle"""
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puzzle_input = parse(pathlib.Path(path).read_text().strip())
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part1_result = part1(puzzle_input)
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part2_result = part2(puzzle_input)
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return part1_result, part2_result
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def main() -> None:
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for path in sys.argv[1:]:
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print(f"Input File: {path}")
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part1_result, part2_result = solve(path)
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print(f"Part 1 Result: {part1_result}")
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print(f"Part 2 Result: {part2_result}")
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if __name__ == "__main__":
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main()
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