76 lines
2.6 KiB
Python
76 lines
2.6 KiB
Python
def generate_difference_table(history):
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"""Generates a difference table for a given history."""
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table = [history]
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while not all(value == 0 for value in table[-1]):
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try:
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next_row = [
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table[-1][i + 1] - table[-1][i] for i in range(len(table[-1]) - 1)
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]
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except IndexError as e:
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print(f"IndexError in generate_difference_table: {e}")
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print(f"Current table: {table}")
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raise
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table.append(next_row)
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return table
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def extrapolate_previous_value(table):
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"""Extrapolates the previous value from the difference table."""
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try:
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for i in range(len(table) - 2, -1, -1):
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table[i].insert(0, table[i][0] - table[i + 1][0])
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except IndexError as e:
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print(f"IndexError in extrapolate_previous_value: {e}")
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print(f"Current table: {table}")
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raise
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return table[0][0]
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def solve_puzzle(filename):
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"""Solves the puzzle by reading histories from the file and summing their extrapolated previous values."""
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total = 0
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try:
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with open(filename, "r") as file:
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for line in file:
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try:
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history = [int(x) for x in line.split()]
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diff_table = generate_difference_table(history)
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prev_value = extrapolate_previous_value(diff_table)
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total += prev_value
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except ValueError as e:
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print(f"ValueError processing line '{line}': {e}")
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except IndexError as e:
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print(f"IndexError processing line '{line}': {e}")
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except FileNotFoundError:
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print(f"FileNotFoundError: The file {filename} was not found.")
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raise
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except Exception as e:
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print(f"Unexpected error processing file {filename}: {e}")
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raise
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return total
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def test():
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"""Runs the test using the test.txt file and asserts the expected outcome for the second part of the puzzle."""
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expected = 2 # Expected result from the test data for the second part
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try:
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result = solve_puzzle("../test.txt")
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assert result == expected, f"Test failed: Expected {expected}, got {result}"
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print("Test passed successfully.")
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except AssertionError as e:
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print(e)
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raise
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def main():
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"""Main function to run the test and then solve the puzzle."""
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print("Running test for the second part...")
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test()
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print("Test completed. Solving the puzzle for the second part...")
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result = solve_puzzle("../input.txt")
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print(f"Puzzle result for the second part: {result}")
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if __name__ == "__main__":
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main()
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