wip

Pt 2 is almost there. Need a better flood fill
algorithm.

2025-python/output/__init__.py

@@ -91,10 +91,10 @@ def vdbg(seen, mask=("#", "."), M=None):
         r = max(r, x)
         b = max(b, y)
         l = min(l, x)
-    H = b + 1
-    W = r + 1
-    osr = 0 #t
-    osc = 0 #l
+    H = b - t + 1
+    W = r - l + 1
+    osr = t
+    osc = l
     C, Z = mask
     def _m(r, c):
         return M[r][c] if M else Z

2025-python/output/day_09.py

@@ -1,28 +1,19 @@
-from math import inf
 from itertools import combinations
+import PIL
 
-from output import ints
+from output import svg, D, ints, vdbg
 
 
 def solve(data):
     p1 = 0
     p2 = 0
     A = [tuple(ints(pos)) for pos in data.splitlines()]
-    T = inf
-    R = 0
-    B = 0
-    L = inf
-    for r, c in A:
-        T = min(r, T)
-        R = max(c, R)
-        B = max(r, B)
-        L = min(c, L)
+
     S = A[0]
     V = set()
-    W = set()
+    B = set()
     while True:
         V.add(S)
-        W.add(S)
         y, x = S
         he = [(r, c) for r, c in A if r == y and (r, c) not in V]
         ve = [(r, c) for r, c in A if c == x and (r, c) not in V]
@@ -37,41 +28,61 @@ def solve(data):
         y2, x2 = E
         for r in range(min(y, y2), max(y, y2) + 1):
             for c in range(min(x, x2), max(x, x2) + 1):
-                W.add((r, c))
+                B.add((r, c))
         if E == A[0]:
             break
         S = E
-    V = V | W
+    # find out a better start for Flood fill by visualizing
+    Y = 50000
+    X = 25000
+    # or, find a way to floodfill without BFS
+    # end
+    y, x = Y, X
+    Q = [(y, x)]
+    V = V | B
+    while Q:
+        yx = Q.pop()
+        if yx in V:
+            continue
+        V.add(yx)
+        y, x = yx
+        for dy, dx in D:
+            Q.append((dy + y, dx + x))
     for a, b in combinations(A, r=2):
         y1, x1 = a
         y2, x2 = b
         x = abs(x1 - x2) + 1
         y = abs(y1 - y2) + 1
         p1 = max(p1, x * y)
-        if _within(W, a, b, T, R, B, L):
+        if (
+            len(
+                set(
+                    [
+                        (min(y1, y2), min(x1, x2)),
+                        (min(y1, y2), max(x1, x2)),
+                        (max(y1, y2), min(x1, x2)),
+                        (max(y1, y2), max(x1, x2)),
+                    ]
+                )
+                - V
+            )
+            == 0
+        ):
             p2 = max(p2, max(p2, x * y))
     return p1, p2
 
 
-def _within(W, a, b, T, R, B, L):
-    y1, x1 = a
-    y2, x2 = b
-    for r in range(min(y1, y2) + 1, max(y1, y2)):
-        for c in range(min(x1, x2) + 1, max(x1, x2)):
-            if (r, c) in W:
-                continue
-            for s, e in [(T, r), (r, B)]:
-                z = sum((nr, c) in W for nr in range(s, e))
-                if z and z % 2 == 0:
-                    return False
-            for s, e in [(L, c), (c, R)]:
-                z = sum((r, nc) in W for nc in range(s, e))
-                if z and z % 2 == 0:
-                    return False
-    return True
-
-
 if __name__ == "__main__":
+    inp = """
+7,1
+11,1
+11,7
+9,7
+9,5
+2,5
+2,3
+7,3    """.strip()
+
     with open("./input/09.txt", "r") as f:
         inp = f.read().strip()