2024 day9-10

1 files changed, 58 insertions, 0 deletions

diff --git a/2024/day09/solve2.py b/2024/day09/solve2.py
new file mode 100644
index 0000000..bed2825
--- /dev/null
+++ b/2024/day09/solve2.py
@@ -0,0 +1,58 @@
+with open("input") as f:

+    data = f.read()

+

+blocks = []

+last_file_id = None

+for idx, count in enumerate(data):

+    block_char = "." if idx % 2 == 1 else str(idx // 2)

+    for ii in range(int(count)):

+        blocks.append(block_char)

+        last_file_id = block_char

+

+end_seek_idx = len(blocks) - 1

+for file in range(int(last_file_id), -1, -1):

+    file_block = str(file)

+    file_start_block = None

+    file_end_block = None

+    for idx in range(end_seek_idx, -1, -1):

+        if blocks[idx] == file_block:

+            if file_end_block is None:

+                file_end_block = idx

+        else:

+            if file_end_block is not None:

+                file_start_block = idx + 1

+                end_seek_idx = idx

+                break

+    else:

+        break

+

+    file_size = file_end_block - file_start_block + 1

+

+    empty_block_size = 0

+    for idx, block_content in enumerate(blocks):

+        if idx > end_seek_idx:

+            break

+

+        if block_content == ".":

+            empty_block_size += 1

+        else:

+            empty_block_size = 0

+

+        if empty_block_size == file_size:

+            empty_block_start = idx - file_size + 1

+            for ii in range(file_size):

+                blocks[empty_block_start + ii], blocks[file_start_block + ii] = blocks[file_start_block + ii], blocks[empty_block_start + ii]

+            break

+

+def calculate_checksum(blocks: list[str]):

+    checksum = 0

+    for index, elem in enumerate(blocks):

+        if elem == ".":

+            continue

+

+        checksum += index * int(elem)

+

+    return checksum

+

+

+print(calculate_checksum(blocks))