Started with 2020 because I need stars for Beeminder

2020/d3.py

@@ -0,0 +1,33 @@
+from lib import get_data, Grid2D
+
+
+def part_1(data):
+    g = Grid2D(data)
+
+    pos = (0, 0)
+    r = 0
+    while pos[0] < g.n_rows:
+        if g[pos] == "#":
+            r += 1
+        pos = (pos[0] + 1, (pos[1] + 3) % g.n_cols)
+    print(r)
+
+    fr = 1
+    for dr, dc in [(1, 1), (1, 3), (1, 5), (1, 7), (2, 1)]:
+        pos = (0, 0)
+        r = 0
+        while pos[0] < g.n_rows:
+            if g[pos] == "#":
+                r += 1
+            pos = (pos[0] + dr, (pos[1] + dc) % g.n_cols)
+        fr *= r
+    print(fr)
+
+
+def main():
+    data = get_data(__file__)
+    part_1(data)
+
+
+if __name__ == "__main__":
+    main()