advent-of-code/2022/python/day12.py

117 lines
3.1 KiB
Python

import shared
import matrix
from dijkstar import Graph, find_path, algorithm
#def dj_walk(mx, start, end):
# def next_cost(c, val):
# if val > c+1:
# return 9999
# else:
# return val
#
# start = start[1], start[0]
# end = end[1], end[0]
#
# # Dijkstra from RedBlobGames
# frontier = PriorityQueue()
# frontier.put(start, 0)
# came_from = dict()
# cost_so_far = dict()
# came_from[start] = None
# cost_so_far[start] = 0
# last = None
# while not frontier.empty():
# x, y = frontier.get()
# cur = (x, y)
# if cur == end:
# break
# for _n in matrix.get_neighbors(mx, x=x, y=y, _dict=True):
# nxt = (_n["x"], _n["y"])
# v = _n["value"]
#
# new_cost = next_cost(cost_so_far[cur], v)
# if nxt not in cost_so_far or new_cost < cost_so_far[nxt]:
# cost_so_far[nxt] = new_cost
# priority = new_cost
# frontier.put(nxt, priority)
# came_from[nxt] = cur
# last = cur
# print(len(cost_so_far))
criteria = lambda _cur, _neighbor: _neighbor - _cur <= 1
def build_graph(mx):
graph = Graph()
for y, row in enumerate(mx):
for x, _ in enumerate(row):
neighbors = matrix.valid_neighbors(mx, x=x, y=y, criteria=criteria)
for neighbor in neighbors:
graph.add_edge((y, x), (neighbor['y'],neighbor['x']), 1)
return graph
#SEEN = []
#def walk(mx, y, x, seen=[]):
# print(len(seen))
# valid_next = matrix.valid_neighbors(mx, y, x, criteria=criteria)
# print(valid_next)
# matrix.highlight( mx, red=seen, green=[ *valid_next, ], blue=[ END, ],)
# for next_yx in valid_next:
# if next_yx not in seen:
# seen.append(next_yx)
# _y, _x = next_yx
# walk(mx, _y, _x, seen)
# else:
# seen.append(next_yx)
def elev(yx):
y,x = yx
return mx[y][x]
def part1(mx):
start = matrix.find_in_matrix(mx, "S")
end = matrix.find_in_matrix(mx, "E")
mx[start[0]][start[1]] = "a"
mx[end[0]][end[1]] = "z"
matrix.apply_to_all(mx, lambda x: ord(x) - ord('a'))
#walk(mx, cur[0],cur[0], seen=[(cur[0],cur[1])])
#dj_walk(mx, cur, END)
graph = build_graph(mx)
path = find_path(graph, start, end)
print(len(path.nodes))
def part2(mx):
end = matrix.find_in_matrix(mx, "E")
s = matrix.find_in_matrix(mx, "S")
mx[s[0]][s[1]] = "a"
mx[end[0]][end[1]] = "z"
starts = matrix.find_in_matrix(mx, 'a', one=False)
matrix.apply_to_all(mx, lambda x: ord(x) - ord('a'))
graph = build_graph(mx)
n_counts = []
for start in starts:
#walk(mx, cur[0],cur[0], seen=[(cur[0],cur[1])])
#dj_walk(mx, cur, END)
try:
path = find_path(graph, start, end)
n_counts.append(len(path.nodes)-1)
except algorithm.NoPathError:
pass
print(n_counts)
print(min(n_counts))
def main():
mx = matrix.load_matrix_file(shared.get_fname(12), matrix.split_word_to_chr_list)
#part1(mx)
part2(mx)
if __name__ == "__main__":
main()