#!/usr/bin/env python3

import sys, re
from copy import deepcopy


VALVES = {'V': [], 'E': [], 'w': {}}


def parse(line):
    g = re.compile(r"Valve (?P<valve>\w{2}) has flow rate=(?P<fr>\d+); tunnel(s)? lead(s)? to valve(s)? (?P<tunnel>(\w{2}(, )?)*)").search(line)
    vc = g.group('valve') + 'C'
    vo = g.group('valve') + 'O'
    es = g.group('tunnel').split(', ')
    VALVES['V'] += [vc,vo]
    VALVES['E'].append((vc,vo))
    for e in es:
        VALVES['E'].append((vo,e+'C'))
        VALVES['E'].append((vc,e+'C'))
        VALVES['w'][(vo,e+'C')] = 0
        VALVES['w'][(vc,e+'C')] = 0
    VALVES['w'][(vc,vo)] = int(g.group('fr'))

def Init(G,s,k):
    d = {}
    o = {}
    for v in G['V']:
        d[v] = [-1] * k
        o[v] = [[]] * k
    d[s] = [0] * k
    return d, o

def anti_relax(u,v,w,i,d,k,o):
    if d[v][i] < d[u][i-1] + w[(u,v)] * (k-i):
        d[v][i] = d[u][i-1] + w[(u,v)] * (k-i)
        o[v][i] = o[u][i-1] + [u]

def find_path(G,s,k):
    d,o = Init(G,s,k)
    for i in range(k):
        di = deepcopy(d)
        for (u,v) in G['E']:
            if d[u][i-1] > -1 and not (u[:2] == v[:2] and v in o[u][i-1]): anti_relax(u,v,G['w'],i,di,k,o)
        d = deepcopy(di)
    return max(map(max,d.values()))

def Init_double(G,s,k):
    d = {}
    o = {}
    for v in G['V']:
        d[v] = [-1] * k
        o[v] = [[]] * k
    d[s] = [0] * k
    return d, o

def anti_relax_double(u,v,w,i,d,k,o):
    if d[v][i] < d[u][i-1] + w[(u,v)] * (k-i):
        d[v][i] = d[u][i-1] + w[(u,v)] * (k-i)
        o[v][i] = o[u][i-1] + [u]

def find_double_path(G,s,k):
    d,o = Init_double(G,s,k)
    for i in range(k):
        di = deepcopy(d)
        for (u,v) in G['E']:
            if d[u][i-1] > -1 and not (u[:2] == v[:2] and v in o[u][i-1]):
                anti_relax_double(u,v,G['w'],i,di,k,o)
        for (u,v) in G['E']:
            if d[u][i-1] > -1 and not (u[:2] == v[:2] and (v in o[u][i-1] or v in o[u][i])):
                anti_relax_double(u,v,G['w'],i,di,k,o)
        d = deepcopy(di)
    return max(map(max,d.values()))


if __name__ == '__main__':
    [parse(line.strip('\n')) for line in open(sys.argv[1])]

    m = find_path(VALVES,'AAC',29)
    
    # start (s): AA, length (k): 30, 

    # challenge 1
    res1 = str(m)
    print("challenge 1:" + "\n" +  res1 + "\n")

    # challenge 2
    m = find_double_path(VALVES,'AAC',25)
    # missing: magic!
    print(m)
    res2 = ""
    print("challenge 2:" + "\n" +  res2 + "\n")