My Advent of Code solutions in Python.
kevinyap.ca/2019/12/going-fast-in-advent-of-code/
advent-of-code
python
Add solution for 2023/10 part 1
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2023/day10.py
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2023/day10.py
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import fileinput
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from utils import Point, DIRS, N, E, S, W
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def transition(node, tile, dirr):
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if tile == '|':
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if dirr == N:
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return N, 1
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elif dirr == S:
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return S, 1
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else:
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return None, 0
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elif tile == '-':
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if dirr == W:
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return W, 1
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elif dirr == E:
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return E, 1
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else:
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return None, 0
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elif tile == 'L':
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if dirr == W:
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return S, 1
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elif dirr == N:
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return E, 1
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elif tile == 'J':
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if dirr == N:
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return W, 1
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elif dirr == E:
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return S, 1
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else:
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return None, 1
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elif tile == '7':
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if dirr == E:
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return N, 1
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elif dirr == S:
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return W, 1
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else:
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return None, 0
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elif tile == 'F':
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if dirr == S:
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return E, 1
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elif dirr == W:
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return N, 1
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else:
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return None, 0
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elif tile == 'S':
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return direction, 1
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return None, 0
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def walk_loop(graph, start, direction):
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loop = [start]
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node = start
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while True:
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direction, good = transition(node, graph[node], direction)
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if not good:
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return None
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node += direction
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loop.append(node)
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if node == start:
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return loop
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board = {}
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for y, line in enumerate(fileinput.input()):
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for x, c in enumerate(line.strip()):
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board[Point(x, y)] = c
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# Solve part 1.
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start = [p for p, v in board.items() if v == 'S'][0]
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for direction in DIRS:
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loop = walk_loop(board, start, direction)
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if loop:
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print("Part 1:", len(loop) // 2)
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break
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# TODO: Solve part 2 programmatically.