Jake Pullen
84 lines
2.6 KiB
Python
84 lines
2.6 KiB
Python
import math
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with open(r'advent_of_code\2023\day_8\input.txt', 'r') as file:
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input = file.read()
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#print(input)
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test_input = '''LR
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11A = (11B, XXX)
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11B = (XXX, 11Z)
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11Z = (11B, XXX)
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22A = (22B, XXX)
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22B = (22C, 22C)
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22C = (22Z, 22Z)
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22Z = (22B, 22B)
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XXX = (XXX, XXX)'''
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#test_input = '''LLR
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#AAA = (BBB, BBB)
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#BBB = (AAA, ZZZ)
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#ZZZ = (ZZZ, ZZZ)'''
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input = input.split('\n')
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#input = test_input.split('\n')
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top_line = input[0]
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#print(top_line)
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# change L to 0 and R to 1 and split into list
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top_line = list(top_line)
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top_line = [s.replace('L', '0').replace('R', '1') for s in top_line]
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#print(top_line)
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# create a dictionary of instructions, where is the key is a range of numbers and the value is a number from the top line
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instructions = {}
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for i in range(0, len(top_line)):
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instructions[i] = top_line[i]
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#print(instructions)
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# now we need to take the rest of the input and and split it into a dictionary where the key is left of the = sign
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# and the value is a list of the right of the = sign split by commas and stripped of whitespace and brackets
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guide = input[1:]
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#print(guide)
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if guide[0] == '':
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guide.pop(0)
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for i in range(0, len(guide)):
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if '=' in guide[i]:
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guide[i] = guide[i].replace(' ', '').replace('(', '').replace(')', '').split('=')
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guide[i][1] = guide[i][1].split(',')
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guide[i][1] = [x.strip() for x in guide[i][1]]
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# now we need to create a dictionary where the key is the left of the = sign and the value is a list of the right of the = sign split by commas and stripped of whitespace and brackets
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guide_dict = {}
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for i in range(0, len(guide)):
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guide_dict[guide[i][0]] = guide[i][1]
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# Initialize current_nodes as a list of starting nodes
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current_nodes = [node for node in guide_dict.keys() if node.endswith('A')]
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solve_steps = []
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# Perform the operation
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# for each start node we found that ends in A
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# we need to work out how many steps it takes to get to a node that ends in Z
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for current_node in current_nodes:
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step = 0
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#while current node does not end with z
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while current_node:
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# Use modulo to wrap step around if it's greater than the length of instructions
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choose_items = int(instructions[step % len(instructions)])
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next_node = guide_dict[current_node][choose_items]
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current_node = next_node
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step += 1
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if current_node.endswith('Z'):
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break
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solve_steps.append(step)
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print(solve_steps)
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# once we find out how many steps it takes to get to Z we need to find the lowest common denominator of all the steps
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lcm_value = solve_steps[0]
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for number in solve_steps[1:]:
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lcm_value = lcm_value * number // math.gcd(lcm_value, number)
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print(lcm_value) |