day 14, proper cycle detection, merge both path, enable codon

d14/part1.py

@@ -1,30 +0,0 @@
-import sys
-
-# load ptf flat
-G = [list(l) for l in sys.stdin.read().splitlines()]
-W = len(G[0])
-H = len(G)
-print(W,H)
-
-# move far north each com
-for x in range(W):
-    for y in range(H):
-        print(f'{x=},{y=} = {G[y][x]}')
-        if G[y][x] == "O":
-            for j in range(y-1,0-1,-1):
-                print(f'{j=}')
-                if G[j][x] == '.':  # can go north
-                    print(f'north, {j=}')
-                    G[j][x] = "O"
-                    G[j+1][x] = "."
-                else:
-                    break
-
-S = 0              
-for y,row in enumerate(G):
-    print(''.join(row))
-    S += (H-y)*row.count('O')
-print(S)
-
-# compute
-

d14/part2.py

@@ -1,59 +0,0 @@
-import sys
-
-I = sys.stdin.read().splitlines()
-G = [list(l) for l in I]
-W = len(G[0])
-H = len(G)
-
-def north():
-    for x in range(W):
-        for y in range(H):
-            if G[y][x] == "O":
-                for j in range(y-1,0-1,-1):
-                    if G[j][x] == '.':
-                        G[j][x] = "O"
-                        G[j+1][x] = "."
-                    else:
-                        break
-
-def south():
-    for x in range(W):
-        for y in range(H-1,0-1,-1):
-            if G[y][x] == "O":
-                for j in range(y+1,W,1):
-                    if G[j][x] == '.':
-                        G[j][x] = "O"
-                        G[j-1][x] = "."
-                    else:
-                        break
-
-def east():
-    for y in range(H):
-        for x in range(W-1,0-1,-1):
-            if G[y][x] == "O":
-                for i in range(x+1,H,1):
-                    if G[y][i] == '.':
-                        G[y][i] = "O"
-                        G[y][i-1] = "."
-                    else:
-                        break
-
-
-def west():
-    for y in range(H):
-        for x in range(W):
-            if G[y][x] == "O":
-                for i in range(x-1,0-1,-1):
-                    if G[y][i] == '.':
-                        G[y][i] = "O"
-                        G[y][i+1] = "."
-                    else:
-                        break
-
-for _ in range(1_000):
-    north()
-    west()
-    south()
-    east()
-
-print(sum((H-y)*row.count('O') for y,row in enumerate(G)))

d14/run.py

@@ -0,0 +1,49 @@
+import sys
+
+I = sys.stdin.read().splitlines()
+G = [list(l) for l in I]
+R = len(G)
+C = len(G[0])
+
+def rotate(G, F):
+  for r in range(R):
+    for c in range(C):
+      F[c][R-1-r] = G[r][c]
+
+def tilt(G):
+    for x in range(C):
+        for y in range(R):
+            if G[y][x] == "O":
+                for j in range(y-1,0-1,-1):
+                    if G[j][x] == '.':
+                        G[j][x] = "O"
+                        G[j+1][x] = "."
+                    else:
+                        break
+
+score = lambda: sum((R-y)*row.count('O') for y,row in enumerate(G))
+
+cache = {}
+F = [['?' for _ in range(C)] for _ in range(R)]  # pre-allocate saves 10% time (no GC)
+
+target = 1_000_000_000
+t = 0
+while t<target:
+  print(t, end='\r')
+  t += 1
+  for j in range(4):
+    tilt(G)
+    if t==1 and j==0:  # part 1
+      print(score())
+    rotate(G, F); F, G = G, F
+  #Gh = tuple(tuple(row) for row in G)
+  Gh = ''.join(''.join(row) for row in G)
+  if Gh in cache:
+    cycle_length = t-cache[Gh]
+    print(f'{t=}, {cycle_length=}')
+    amt = (target-t)//cycle_length
+    t += amt * cycle_length
+  cache[Gh] = t
+
+print(t, score())
+