#!/usr/bin/env python3

# import numpy as np
from functools import reduce
from re import findall
from copy import deepcopy
from collections import defaultdict
import sys

# filename = "in/day24.ref"
filename = "in/day24.pzl"
data = open(filename).read()
lines = [line for line in data.rstrip('\n').split('\n')]
# print(lines)

D = dict()
for y,line in enumerate(lines):
    for x,val in enumerate(line):
        if val != '.':
            D[(y,x)] = val

def get_max(D):
    min_y = 1000
    max_y = 0
    min_x = 1000
    max_x = 0
    for y,x in D:
        min_y = min(min_y, y)
        max_y = max(max_y, y)
        min_x = min(min_x, x)
        max_x = max(max_x, x)
    return min_y, max_y, min_x, max_x

def print_grid(D, P):
    min_y, max_y, min_x, max_x = get_max(D)
    for y in range(min_y, max_y + 1):
        for x in range(min_x, max_x + 1):
            if (y,x) in P:
                print('E',end='')
            elif (y,x) in D:
                print(D[(y,x)][0],end='')
            else:
                print('.', end='')
        print()
    print()
    print()

min_y, max_y, min_x, max_x = get_max(D)

start_x = 1
end_x = max_x - 1

def get_next_D(D):
    Dn = defaultdict(list)
    for (y,x) in D:
        for val in D[(y,x)]:
            if val == '#':
                Dn[(y,x)].append('#')

            elif val == '>':
                nx = x + 1
                if nx == max_x:
                    nx = 1
                Dn[(y,nx)].append('>')

            elif val == '<':
                nx = x - 1
                if nx == 0:
                    nx = max_x - 1
                Dn[(y,nx)].append('<')

            elif val == 'v':
                ny = y + 1
                if ny == max_y:
                    ny = 1
                Dn[(ny,x)].append('v')

            elif val == '^':
                ny = y - 1
                if ny == 0:
                    ny = max_y - 1
                Dn[(ny,x)].append('^')
    return Dn

def dfs(Dstart, Pstart, Pend):
    P = Pstart
    D = Dstart

    it = 0
    for _ in range(1000):
        it += 1
        Pn = set()

        D = get_next_D(D)

        for y,x in P:
            for dy,dx in [0,0], [1,0], [-1,0], [0,1], [0,-1]:
                if 0 <= y+dy <= max_y and 0 <= x+dx <= max_x:
                    if (y+dy, x+dx) not in D:
                        Pn.add((y+dy,x+dx))
        P = Pn

        # print_grid(D, P)
        # print(P)

        for (y,x) in P:
            if (y,x) in Pend:
                return D, it


Pstart = set()
Pstart.add((0,1))
Pend = set()
Pend.add((max_y, max_x-1))

D, t1 = dfs(D, Pstart, Pend)
D, t2 = dfs(D, Pend, Pstart)
D, t3 = dfs(D, Pstart, Pend)

res1 = t1
res2 = t1 + t2 + t3

print('res1:', res1)
print('res2:', res2)