day 18 ivy solution

not sure how this ever worked

day16/sol.py

@@ -152,6 +152,10 @@ def solve():
             m -= 1
         return c
 
+    def worst2(node):
+        _, _, min1, min2, closed = node
+        return min(min1,min2) * pressure(closed)
+
     def is_goal2(node):
         _, _, min1, min2, closed = node
         return min1 == 0 and min2 == 0 or closed == all_open
@@ -209,7 +213,7 @@ def solve():
     minutes = 26
     start2 = (AA, AA, minutes, minutes, all_closed)
     info.clear()
-    c, _, path = astar.search(start2, is_goal2, neighbors2, heuristic2)
+    c, _, path = astar.search(start2, is_goal2, neighbors2, heuristic2, worst=worst2)
     print(c)
     print(max_pressure*minutes - c)
 

day18/sample1.in

@@ -0,0 +1,13 @@
+2,2,2
+1,2,2
+3,2,2
+2,1,2
+2,3,2
+2,2,1
+2,2,3
+2,2,4
+2,2,6
+1,2,5
+3,2,5
+2,1,5
+2,3,5

day18/sol.ivy

@@ -0,0 +1,52 @@
+) get "input.ivy"
+
+sample = 13 3 rho 2 2 2 1 2 2 3 2 2 2 1 2 2 3 2 2 2 1 2 2 3 2 2 4 2 2 6 1 2 5 3 2 5 2 1 5 2 3 5
+#input = sample
+
+) origin 0
+
+op makeGrid coords =
+    lo = min/ transp coords
+    hi = max/ transp coords
+    coords = 1 1 1 + coords - lo
+    dim = 2 + (1 + hi - lo)
+    g = ,dim rho 0
+    g[dim decode transp coords] = 1
+    dim rho g
+
+op makeBorder dim =
+    g = (dim-2) rho 0
+    g = 1,(2 0 1 transp g),1
+    g = 1,(2 0 1 transp g),1
+    g = 1,(2 0 1 transp g),1
+    g
+
+op n twist a = 1 0 2 transp n flip (1 0 2 transp a)
+
+op grow a = (1 rot a) or (-1 rot a) or (1 flip a) or (-1 flip a) or (1 twist a) or (-1 twist a)
+op sides a = (1 rot a) + (-1 rot a) + (1 flip a) + (-1 flip a) + (1 twist a) + (-1 twist a)
+
+lava = makeGrid input
+
+"npoints = "; +/ ,lava
+#lava
+
+#border = makeBorder rho lava
+#or/, lava and border # should == 0
+
+op a flood walls =
+    x = grow a
+    b = (a or x) and not walls
+    and/, a == b: a
+    b flood walls
+
+op solve2 lava =
+    water = (makeBorder rho lava) flood lava
+    +/, lava * sides water
+
+op solve1 lava =
+    air = not lava
+    +/, lava * sides air
+
+"part 1 ="; solve1 lava
+"part 2 ="; solve2 lava

day18/sol.py

@@ -0,0 +1,62 @@
+import numpy
+
+N = 23
+
+def solve():
+    lava = numpy.zeros((N,N,N), dtype=numpy.int32)
+    for line in open("input"):
+        x,y,z = map(int, line.strip().split(","))
+        lava[x,y,z] = 1
+
+    lava = numpy.pad(lava, (1,1), constant_values=0)
+
+    # part 1
+    area = count_touching(lava, lava^1)
+    print(area)
+
+    # part 2
+    border = numpy.zeros((N,N,N), dtype=numpy.int32)
+    border = numpy.pad(border, (1,1), constant_values=1)
+
+    water = flood(lava, border)
+    #print(water)
+
+    area = count_touching(lava, water)
+    print(area)
+
+
+def count_touching(A, B):
+    """counts the number of places a cell in A touches a cell in B
+    (assumes a 1-cell padding around the edge which is not counted)"""
+    n = 0
+    for x in range(1,N+1):
+        for y in range(1,N+1):
+            for z in range(1,N+1):
+                if A[x,y,z]:
+                    n += B[x-1,y,z]
+                    n += B[x+1,y,z]
+                    n += B[x,y-1,z]
+                    n += B[x,y+1,z]
+                    n += B[x,y,z-1]
+                    n += B[x,y,z+1]
+    return n
+
+def flood(lava, border):
+    def roll(a, axis, amount):
+        return numpy.roll(a, amount, axis=axis)
+
+    a = border
+    while True:
+        x = roll(a, 0, -1)
+        x |= roll(a, 0, +1)
+        x |= roll(a, 1, -1)
+        x |= roll(a, 1, +1)
+        x |= roll(a, 2, -1)
+        x |= roll(a, 2, +1)
+        x &= ~lava
+        b = a | x
+        if (a == b).all():
+            return a
+        a = b
+
+solve()

lib/astar.py

@@ -1,6 +1,6 @@
 from heapq import heappush, heappop
 
-def search(start, is_goal, neighbors, heuristic=None):
+def search(start, is_goal, neighbors, heuristic=None, worst=None):
     if heuristic == None:
         def heuristic(x):
             return 0
@@ -16,6 +16,8 @@ def search(start, is_goal, neighbors, heuristic=None):
         i += 1
         heappush(q, (heuristic(s), i, s, None))
     done = {}
+    if worst:
+        best_worst = min(worst(s) for s in start)
     while q:
         z, _, this, prev = heappop(q)
         if this in done:
@@ -27,6 +29,7 @@ def search(start, is_goal, neighbors, heuristic=None):
 
         if is_goal(this):
             print("astar: visited", len(done), "nodes")
+            print("astar: pending", len(q), "nodes")
             # reconsruct the path
             n = this
             path = []
@@ -37,11 +40,20 @@ def search(start, is_goal, neighbors, heuristic=None):
             return cost_so_far, this, path
 
         for c, n in neighbors(this):
-            if n not in done:
+            c = cost_so_far + c
-                # calculate the "reduced cost"
+            if n not in done or c < done[n][0]:
-                c = cost_so_far + c + heuristic(n)
+                h = heuristic(n)
+                if worst:
+                    if c+h > best_worst:
+                        # if the best possible cost for this node
+                        # is worse than the lowest worst-case cost we've seen
+                        # then don't even bother exploring it
+                        continue
+                    w = worst(n)
+                    if c+w < best_worst:
+                        best_worst = c+w
                 i += 1
-                heappush(q, (c, i, n, this))
+                heappush(q, (c+h, i, n, this))
 
     return float('inf'), None, []