import os with open(r'advent_of_code\2023\day_8\input.txt', 'r') as file: input = file.read() #print(input) test_input = '''LR 11A = (11B, XXX) 11B = (XXX, 11Z) 11Z = (11B, XXX) 22A = (22B, XXX) 22B = (22C, 22C) 22C = (22Z, 22Z) 22Z = (22B, 22B) XXX = (XXX, XXX)''' #test_input = '''LLR #AAA = (BBB, BBB) #BBB = (AAA, ZZZ) #ZZZ = (ZZZ, ZZZ)''' input = input.split('\n') #input = test_input.split('\n') top_line = input[0] #print(top_line) # change L to 0 and R to 1 and split into list top_line = list(top_line) top_line = [s.replace('L', '0').replace('R', '1') for s in top_line] #print(top_line) # create a dictionary of instructions, where is the key is a range of numbers and the value is a number from the top line instructions = {} for i in range(0, len(top_line)): instructions[i] = top_line[i] #print(instructions) # 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 # and the value is a list of the right of the = sign split by commas and stripped of whitespace and brackets guide = input[1:] #print(guide) if guide[0] == '': guide.pop(0) for i in range(0, len(guide)): if '=' in guide[i]: guide[i] = guide[i].replace(' ', '').replace('(', '').replace(')', '').split('=') guide[i][1] = guide[i][1].split(',') guide[i][1] = [x.strip() for x in guide[i][1]] # 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 guide_dict = {} for i in range(0, len(guide)): guide_dict[guide[i][0]] = guide[i][1] print(guide_dict) # starting at 'AAA' we need to follow the instructions to get to the bottom of the tree # we need to follow the instructions until we get to ZZZ # if we run out of instructions before we get to ZZZ then we need to repeat the instructions from where we are # Convert the dictionary to a list # Perform the operation # Initialize current_nodes as a list of starting nodes current_nodes = [node for node in guide_dict.keys() if node.endswith('A')] step = 0 while not all(node.endswith('Z') for node in current_nodes): #print(current_nodes) print(step) # Use modulo to wrap step around if it's greater than the length of instructions choose_items = int(instructions[step % len(instructions)]) # Update each node in the list current_nodes = [guide_dict[node][choose_items] for node in current_nodes] step += 1 print(f'finished in {step} steps, current nodes are {current_nodes}') print(current_nodes)