day 16, part 2 never ends, research space is too big

d16/part1.py

@@ -0,0 +1,47 @@
+import sys
+import re
+
+pat = re.compile('Valve ([A-Z]{2}) has flow rate=([0-9]+); tunnels? leads? to valves? ([ ,A-Z]+)')
+P = dict()
+for i,l in enumerate(sys.stdin.read().splitlines()):
+    g = pat.search(l)
+    p = int(g[2])
+    P[g[1]] = (i, p, g[3].split(", "))
+    
+STEPS = int(sys.argv[1])
+ALLO = 0
+for _,(i,p,_) in P.items():
+    if p == 0:
+        ALLO = ALLO | (1<<i) 
+
+cache = {}
+def step(pos="AA", left=STEPS, opens=ALLO):
+    """
+    opens store valves openess 0: closed, 1: open
+                         1 2 3 4 5 6 7 8 9 10
+    eg: 0b1000011110 ->  0 1 1 1 1 0 0 0 0 1
+
+    return : score = max(p*left + open valve if not open and continue, not open valve and continue)
+    """
+    if left <= 0:
+        return 0
+    key = (pos, left, opens)
+    r = cache.get(key, -1)
+    if r >= 0:
+        return r
+    (i, p, nh) = P[pos]
+    is_open = opens & (1 << i)
+    #print(minutes, path, i, bool(is_open), p, nh)
+    a = 0
+    if not is_open:  # also means 0 - worth opening valve ?
+        #print("open", i)
+        left -= 1 # cost to open
+        opens = opens | (1<<i)
+        a = p*(left+30-STEPS) + max(step(n, left-1, opens) for n in nh)
+    b = max(step(n, left-1, opens) for n in nh)
+    r = max(a,b)
+    cache[key] = r
+    return r
+
+print(step())
+

d16/part2.py

@@ -0,0 +1,50 @@
+import sys
+import re
+
+pat = re.compile('Valve ([A-Z]{2}) has flow rate=([0-9]+); tunnels? leads? to valves? ([ ,A-Z]+)')
+P = dict()
+for i,l in enumerate(sys.stdin.read().splitlines()):
+    g = pat.search(l)
+    p = int(g[2])
+    P[g[1]] = (i, p, g[3].split(", "))
+    
+STEPS = int(sys.argv[1])
+ALLO = 0
+for _,(i,p,_) in P.items():
+    if p == 0:
+        ALLO = ALLO | (1<<i) 
+
+cache = {}
+def step(pos1="AA", pos2="AA", left=STEPS, opens=ALLO):
+    """
+    opens store valves openess 0: closed, 1: open
+                         1 2 3 4 5 6 7 8 9 10
+    eg: 0b1000011110 ->  0 1 1 1 1 0 0 0 0 1
+
+    return : score = max(p*left + open valve if not open and continue, not open valve and continue)
+    """
+    if left <= 0:
+        return 0
+    key = (min(pos1, pos2), max(pos1,pos2), left, opens)
+    r = cache.get(key, -1)
+    if r >= 0:
+        return r
+    (i1, p1, nh1) = P[pos1]
+    (i2, p2, nh2) = P[pos2]
+    isopen1 = opens & (1 << i1)
+    isopen2 = opens & (1 << i2)
+    a = b = c = d = 0
+    if pos1 != pos2 and not isopen1 and not isopen2:  # open both if not same, but don't move
+        a = p1*(left+26-STEPS-1) + p2*(left+26-STEPS-1) + step(pos1, pos2, left-1, opens|(1<<i1)|(1<<i2))
+    if not isopen1: # p1 opens, p2 moves
+        b = p1*(left+26-STEPS-1) + max(step(pos1, n2, left-1, opens|(1<<i1)) for n2 in nh2)
+    if not isopen2:  # p1 moves, p2 opens
+        c = p2*(left+26-STEPS-1) + max(step(n1, pos2, left-1, opens|(1<<i2)) for n1 in nh1)
+    # both moves, no new open
+    d = max(step(n1, n2, left-1, opens) for n1 in nh1 for n2 in nh2)
+    r = max(a,b,c,d)
+    cache[key] = r
+    return r
+
+print(step())
+print(len(cache))