py day 13 part 1

README.md

@@ -31,7 +31,7 @@ For the non-notebook sections, tests (`pytest` and `cargo nextest`) are be inclu
 | 10   | ✅⛔  | ✅⛔ | ✅⛔ | |
 | 11   | ✅✅  | ✅✅ | 🕒🕒 | |
 | 12   | ✅⛔  | ✅⛔  | 🕒🕒 | Getting pretty tired of the "do part 1 but with way more data" trend here. |
-| 13   | ✅⛔  | 🕒🕒  | 🕒🕒 | Multiple examples were working in part 2, but something isn't quite working correctly on the actual inputs. |
+| 13   | ✅⛔  | ✅⛔  | 🕒🕒 | Multiple examples were working in part 2, but something isn't quite working correctly on the actual inputs. |
 | 14   | ✅⛔  | ✅⛔ | 🕒🕒 | |
 | 15   | ✅✅  | ✅✅ | 🕒🕒 | This was a nice little break compared to the past week's puzzle offerings. |
 | 16   | ✅✅  | 🕒🕒 | 🕒🕒 | |

py/solutions/day13_1.py

@@ -0,0 +1,89 @@
+from typing import Optional
+
+import pandas as pd
+from IPython.display import Markdown
+from solutions.utils import timer
+
+
+def find_mirror_position(df: pd.DataFrame, v: bool = False, show=False) -> Optional[int]:
+    max_score = 0
+    for i in range(1, len(df) + 1):
+        if i == len(df):
+            # can't split on the last row
+            continue
+
+        top_rows = df.iloc[:i]
+        bottom_rows = df.iloc[i:]
+
+        if len(top_rows) > len(bottom_rows):
+            # shorten top rows
+            top_rows = top_rows.tail(len(bottom_rows))
+        elif len(top_rows) < len(bottom_rows):
+            # shorten bottom rows
+            bottom_rows = bottom_rows.head(len(top_rows))
+
+        # flip the bottom rows' index positions so they (potentially) match the top
+        bottom_rows = bottom_rows.iloc[::-1]
+
+        assert len(bottom_rows) == len(top_rows)
+
+        # string comparisons on just the values is better than trying to compare the whole dataframe
+        # portions, which will include the index values and columns by default
+        t = top_rows.to_string(index=False, header=False)
+        b = bottom_rows.to_string(index=False, header=False)
+        if t == b:
+            df_copy = df.copy()
+            if v:
+                # debug_df = debug_df.transpose()
+                df_copy = df_copy.transpose()
+
+            # last row's index + 1 in `top_rows` is the position of the mirror line
+            last_index = top_rows.index[-1] + 1
+            # 1x for mirroring against a vertical line, 100x for a horizontal line
+            score = last_index * 100 if not v else last_index
+
+            max_score += score
+    return max_score
+
+
+def find_mirror_lines(data: str, show: bool = False):
+    rows = data.split("\n")
+    df = pd.DataFrame([list(line) for line in rows]).astype(int)
+
+    score = 0
+
+    horizontal_line_score = find_mirror_position(df, show=show)
+    if horizontal_line_score is not None:
+        score += horizontal_line_score
+
+    vertical_line_score = find_mirror_position(df.transpose(), v=True, show=show)
+    if vertical_line_score is not None:
+        score += vertical_line_score
+
+    return score
+
+
+@timer
+def solve(inputs: list[str]) -> int:
+    """High-level solution logic to call additional functions as needed."""
+    total_score = 0
+    for block in inputs:
+        total_score += find_mirror_lines(block)
+    return total_score
+
+
+@timer
+def load_input() -> list[str]:
+    """Read from an input file and handle any preprocessing."""
+    return open("../inputs/13.txt").read().strip().replace("#", "1").replace(".", "0").split("\n\n")
+
+
+@timer
+def run() -> None:
+    inputs: list[str] = load_input()
+    solution = solve(inputs)
+    print(f"{solution=}")
+
+
+if __name__ == "__main__":
+    run()

py/tests/day13.py

@@ -1,11 +1,32 @@
 import pytest
+from solutions import day13_1
 
 
-@pytest.mark.skip(reason="TODO")
 def test_part1():
-    pass
+    input_str = (
+        """
+#.##..##.
+..#.##.#.
+##......#
+##......#
+..#.##.#.
+..##..##.
+#.#.##.#.
+
+#...##..#
+#....#..#
+..##..###
+#####.##.
+#####.##.
+..##..###
+#....#..#""".strip()
+        .replace("#", "1")
+        .replace(".", "0")
+        .split("\n\n")
+    )
+    assert day13_1.solve(input_str) == 405
 
 
-@pytest.mark.skip(reason="TODO")
+@pytest.mark.skip(reason="admitted defeat 😢")
 def test_part2():
     pass