day 11 & day 12

2024/day10/day10a.py

@@ -0,0 +1,60 @@
+import sys
+import re
+import heapq
+from collections import defaultdict, Counter, deque
+#import pyperclip as pc
+def pr(s):
+    print(s)
+#    pc.copy(s)
+sys.setrecursionlimit(10**6)
+infile = sys.argv[1] if len(sys.argv)>=2 else '/home/bandeira/git.bandeira/aoc/2024/day10/input.day10'
+p1 = 0
+p2 = 0
+D = open(infile).read().strip()
+G = D.split('\n')
+G = [[int(x) for x in row] for row in G]
+R = len(G)
+C = len(G[0])
+
+def ways1(sr,sc):
+    """How many different 0s can I reach going down from here?"""
+    Q = deque([(sr,sc)])
+    ans = 0
+    SEEN = set()
+    while Q:
+        r,c = Q.popleft()
+        if (r,c) in SEEN:
+            continue
+        SEEN.add((r,c))
+        if G[r][c]==0:
+            ans += 1
+        for dr,dc in [(-1,0),(0,1),(1,0),(0,-1)]:
+            rr = r+dr
+            cc = c+dc
+            if 0<=rr<R and 0<=cc<C and G[rr][cc] == G[r][c]-1:
+                Q.append((rr,cc))
+    return ans
+
+DP = {}
+def ways(r,c):
+    if G[r][c]==0:
+        return 1
+    if (r,c) in DP:
+        return DP[(r,c)]
+    ans = 0
+    for dr,dc in [(-1,0),(0,1),(1,0),(0,-1)]:
+        rr = r+dr
+        cc = c+dc
+        if 0<=rr<R and 0<=cc<C and G[rr][cc] == G[r][c]-1:
+            ans += ways(rr,cc)
+    DP[(r,c)] = ans
+    return ans
+
+for r in range(R):
+    for c in range(C):
+        if G[r][c]==9:
+            p1 += ways1(r,c)
+            p2 += ways(r,c)
+
+pr(p1)
+pr(p2)