part2?!?!!

1 files changed, 31 insertions, 0 deletions

diff --git a/2023/21/solve.py b/2023/21/solve.py
new file mode 100644
index 0000000..df17878
--- /dev/null
+++ b/2023/21/solve.py
@@ -0,0 +1,31 @@
+L = {
+    (i, j): c
+    for (i, l) in enumerate(open("input").readlines())
+    for (j, c) in enumerate(l.strip())
+}
+
+
+def solve1():
+    LIM = 64
+
+    res = 0
+    s = [(i, j) for (i, j) in L if L[(i, j)] == "S"][0]
+    q = [(s, 0)]
+    v = set()
+    while q:
+        p, n = q.pop(0)
+        if n == LIM + 1:
+            continue
+
+        for move in [(0, 1), (1, 0), (0, -1), (-1, 0)]:
+            np = (p[0] + move[0], p[1] + move[1])
+            if np not in L or np in v or L[np] == "#":
+                continue
+            q.append((np, n + 1))
+            v.add(np)
+            if n % 2:
+                res += 1
+    print(res)
+
+
+solve1()