#!/bin/python3

import sys
sys.setrecursionlimit(1500)

hmap = list()

with open('day12.txt', 'r') as f:
    for line in f:
        hmap.append(line.strip())

h = len(hmap)
w = len(hmap[0])

for y in range(h):
    for x in range(w):
        if hmap[y][x] == 'S':
            start = (x, y)
        if hmap[y][x] == 'E':
            end = (x, y)

def get_elevation(char):
    if char == 'S':
        return ord('a')
    if char == 'E':
        return ord('z')
    return ord(char)

def get_adjacents(pos):
    (x, y) = pos
    return [(x-1, y), (x+1, y), (x, y-1), (x, y+1)]

def in_bounds(pos):
    (x, y) = pos
    return x >= 0 and x < w and y >= 0 and y < h

def get_char(hmap, pos):
    (x, y) = pos
    return hmap[y][x]

def valid_jump(hmap, pos, adj):
    poschar = get_char(hmap, pos)
    adjchar = get_char(hmap, adj)
    poselev = get_elevation(poschar)
    adjelev = get_elevation(adjchar)
    return poselev + 1 >= adjelev

best_cost = {}

def find_path(hmap, path, pos):
    if get_char(hmap, pos) == 'E':
        return [path]

    paths = list()
    for adj in get_adjacents(pos):
        if adj not in path and in_bounds(adj) and valid_jump(hmap, pos, adj):
            if adj not in best_cost or best_cost[adj] > len(path):
                best_cost[adj] = len(path)
                new_path = set.copy(path)
                new_path.add(adj)
                paths.extend(find_path(hmap, new_path, adj))
    return paths

shortest = None

paths = find_path(hmap, set([start]), start)
for path in paths:
    if not shortest or len(path) < shortest:
        shortest = len(path)

print('part1', shortest - 1)

trail_lengths = {}

def valid_jump2(hmap, pos, adj):
    poschar = get_char(hmap, pos)
    adjchar = get_char(hmap, adj)
    poselev = get_elevation(poschar)
    adjelev = get_elevation(adjchar)
    return adjelev + 1 >= poselev

def find_trail(hmap, trail, pos):
    for adj in get_adjacents(pos):
        if adj not in trail and in_bounds(adj) and valid_jump2(hmap, pos, adj):
            trail_length = len(trail) + 1
            if adj not in trail_lengths or trail_lengths[adj] > trail_length:
                trail_lengths[adj] = trail_length
                new_trail = list.copy(trail)
                new_trail.append(adj)
                find_trail(hmap, new_trail, adj)

find_trail(hmap, [end], end)

shortest = None

for y in range(h):
    for x in range(w):
        if (x, y) in trail_lengths:
            if get_elevation(get_char(hmap, (x, y))) == ord('a'):
                trail_length = trail_lengths[(x, y)]
                if not shortest or trail_length < shortest:
                    shortest = trail_length

print('part2', shortest - 1)