Jake Pullen
49 lines
1.9 KiB
Python
49 lines
1.9 KiB
Python
with open(r'advent_of_code\2023\day_9\input.txt', 'r') as file:
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input = file.readlines()
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# print(input)
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test_input = '''0 3 6 9 12 15
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1 3 6 10 15 21
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10 13 16 21 30 45'''
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#input = test_input.split('\n')
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def predict_next_number(line, is_reversed=True):
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numbers = [int(number) for number in line.split(' ')]
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if is_reversed == True:
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numbers.reverse() # Reverse the list of numbers
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differences = [numbers[i+1] - numbers[i] for i in range(len(numbers)-1)]
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if len(set(differences)) == 1:
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# The sequence is simple arithmetic
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previous_number = numbers[-1] + differences[0]
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else:
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# The sequence might be quadratic or more complex rule
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second_differences = [differences[i+1] - differences[i] for i in range(len(differences)-1)]
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if len(set(second_differences)) == 1: # The sequence is quadratic
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previous_difference = differences[-1] + second_differences[0]
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previous_number = numbers[-1] + previous_difference
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else:
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# The sequence follows a more complex rule
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differences_stack = [differences]
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while not all(difference == 0 for difference in differences):
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differences = [differences[i+1] - differences[i] for i in range(len(differences)-1)]
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differences_stack.append(differences)
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# Now, work our way back up to predict the previous number
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previous_number = numbers[-1]
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for differences in reversed(differences_stack):
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previous_number += differences[-1] # Add the last difference in the list
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differences.append(previous_number) # Add the predicted number to the end of the list
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return previous_number
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all_predictions = []
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for line in input:
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prediction = predict_next_number(line)
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all_predictions.append(prediction)
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total = 0
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for prediction in all_predictions:
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total += prediction
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print(f'Sum of predictions: {total}') |