import numpy as np
import pandas as pd
import os
from collections import Counter
with open('data-2023-10.txt', 'r') as f:
inp = f.read().splitlines()
# 140 x 140
len(inp)
len(inp[0])
pp = [list(x) for x in inp]
pipes = np.array(pp)
# pipes[1:10]Advent of Code 2023 Day 10
— Day 10: Pipe Maze —
On metal island the ground is covered in pipes.
Find the single giant loop starting at S. How many steps along the loop does it take to get from the starting position to the point farthest from the starting position?
numpy plus finding my way through some pipes.
# find the starting location
my_loc = list(np.where(pipes == 'S'))
# print for good measure
# print(my_loc)
# by simply having a look at the input,
# there is an F to the left and a 7 above -
# let's start by going up
steps = 0
# the moves don't just depend on the cell, but how we came into the cell
# so I think we need four different variables with moves
# variable name: the direction we came into the cell from
# numbers: how we move the location
# string: the direction we go into the next location
moves = {
'right': {
'-': [0,1,'right'],
'J': [-1,0,'up'],
'7': [1,0,'down'],
},
'left': {
'-': [0,-1,'left'],
'L': [-1,0,'up'],
'F': [1,0,'down'],
},
'up': {
'|': [-1,0,'up'],
'7': [0,-1,'left'],
'F': [0,1,'right'],
},
'down': {
'|': [1,0,'down'],
'L': [0,1,'right'],
'J': [0,-1,'left'],
},
}
next_move = [-1,0,'up']
locs = [my_loc]
# keep looping
# we come into the cell with how we got into the cell
# check how we get out of the cell
while True:
steps += 1
# safety
if steps == 1000000: break
# make the move
my_loc[0] += next_move[0]
my_loc[1] += next_move[1]
next_dir = next_move[2]
this_pipe = pipes[my_loc[0], my_loc[1]][0]
locs.append(my_loc)
# print(my_loc)
# print(next_dir)
# print(this_pipe)
# check for a finish
if this_pipe == 'S':
break
# get the next directions to move in the next loop
next_move = moves[next_dir][this_pipe]
steps / 2
# 13226 too high
# half of it, of course
# 66136613.0— Part Two —
Actually, the pipes form a loop.
Figure out whether you have time to search for the nest by calculating the area within the loop. How many tiles are enclosed by the loop?
140*140 # number of pipe locations i.e. input
140*140-13266 # number of locations not in the loop
# 6334 is highest possible6334Create a new array with zeros and convert the pipe loop locations to ones
tracker = np.zeros([140, 140], dtype = int)
# find the starting location
my_loc = list(np.where(pipes == 'S'))
steps = 0
next_move = [-1,0,'up']
# keep looping
# we come into the cell with how we got into the cell
# check how we get out of the cell
while True:
steps += 1
# safety
if steps == 10**6: break
# make the move
my_loc[0] += next_move[0]
my_loc[1] += next_move[1]
next_dir = next_move[2]
this_pipe = pipes[my_loc[0], my_loc[1]][0]
# new bit to track where the pipe goes
tracker[my_loc[0], my_loc[1]] = 1
# tracker[my_loc[0], my_loc[1]] = steps
# print(sum(tracker))
# check for a finish
if this_pipe == 'S':
break
# get the next directions to move in the next loop
next_move = moves[next_dir][this_pipe]
df = pd.DataFrame(tracker)
df.to_csv("pipe-tracker.csv", header=False, index=False)This looks quite good in csv form and conditional formatted google sheets but it’s too much to count it manually without trying to code it first. Easier than counting inside is eliminating the outside ones - probably.
for x in range(140):
tracker[x,0] = 2
tracker[0,x] = 2
tracker[139,x] = 2
tracker[x,139] = 2
for r in range(140):
for c in range(140):
if tracker[r,c] == 0:
if (tracker[r-1,c] == 2 or
tracker[r+1,c] == 2 or
tracker[r,c-1] == 2 or
tracker[r,c+1] == 2):
# update the value to be outside the pipe
tracker[r,c] = 2
for r in range(140):
for c in range(139,-1,-1):
if tracker[r,c] == 0:
if (tracker[r-1,c] == 2 or
tracker[r+1,c] == 2 or
tracker[r,c-1] == 2 or
tracker[r,c+1] == 2):
# update the value to be outside the pipe
tracker[r,c] = 2
for r in range(139,-1,-1):
for c in range(140):
if tracker[r,c] == 0:
if (tracker[r-1,c] == 2 or
tracker[r+1,c] == 2 or
tracker[r,c-1] == 2 or
tracker[r,c+1] == 2):
# update the value to be outside the pipe
tracker[r,c] = 2
for r in range(140):
for c in range(139,-1,-1):
if tracker[r,c] == 0:
if (tracker[r-1,c] == 2 or
tracker[r+1,c] == 2 or
tracker[r,c-1] == 2 or
tracker[r,c+1] == 2):
# update the value to be outside the pipe
tracker[r,c] = 2
df = pd.DataFrame(tracker)
df.to_csv("pipe-tracker-2.csv", header=False, index=False)
(tracker == 0).sum()
# 756 too highnp.int64(756)Nope - could be diagonal into some spots
for x in range(140):
tracker[x,0] = 2
tracker[0,x] = 2
tracker[139,x] = 2
tracker[x,139] = 2
def checker(arr):
for i in range(3):
for j in range(3):
if arr[i,j] == 2:
return True
# no outcome, not a 2
return False
for r in range(140):
for c in range(140):
if tracker[r,c] == 0:
if checker(tracker[r-1:r+2,c-1:c+2]):
# update the value to be outside the pipe
tracker[r,c] = 2
for r in range(139,-1,-1):
for c in range(140):
if tracker[r,c] == 0:
if checker(tracker[r-1:r+2,c-1:c+2]):
# update the value to be outside the pipe
tracker[r,c] = 2
for r in range(140):
for c in range(139,-1,-1):
if tracker[r,c] == 0:
if checker(tracker[r-1:r+2,c-1:c+2]):
# update the value to be outside the pipe
tracker[r,c] = 2
df = pd.DataFrame(tracker)
df.to_csv("pipe-tracker-2.csv", header=False, index=False)
(tracker == 0).sum()
# 740np.int64(740)