Add solution for day 16 PART 1

2022/day16/code.py

@@ -0,0 +1,92 @@
+#!/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")
+