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from typing import Optional
from functools import cmp_to_key
def chart_region(plots: list[list[Optional[str]]], current_pos: tuple[int, int],
charted_positions: list[tuple[int, int]], fence_positions: list[list[tuple[int, int]]]) -> tuple[int, int]:
charted_positions.append(current_pos)
current_plot = plots[current_pos[0]][current_pos[1]]
plot_count = 1
fence_count = 0
row_cnt = len(data)
col_cnt = len(data[0])
for dir_idx, direct in enumerate(((-1, 0), (1, 0), (0, -1), (0, 1))):
new_pos = (current_pos[0] + direct[0], current_pos[1] + direct[1])
if 0 <= new_pos[0] < row_cnt and 0 <= new_pos[1] < col_cnt and plots[new_pos[0]][new_pos[1]] == current_plot:
if new_pos not in charted_positions:
result = chart_region(plots, new_pos, charted_positions, fence_positions)
plot_count += result[0]
fence_count += result[1]
else:
fence_positions[dir_idx].append(current_pos)
fence_count += 1
return plot_count, fence_count
def compare_row_first(item1: tuple[int, int], item2: tuple[int, int]):
row_diff = item1[0] - item2[0]
if row_diff != 0:
return row_diff
return item1[1] - item2[1]
def compare_col_first(item1: tuple[int, int], item2: tuple[int, int]):
col_diff = item1[1] - item2[1]
if col_diff != 0:
return col_diff
return item1[0] - item2[0]
def calculate_discount(fence_positions: list[list[tuple[int, int]]]) -> int:
adjacents = 0
for charted_positions in fence_positions:
charted_positions.sort(key=cmp_to_key(compare_row_first))
last_pos = None
for current_pos in charted_positions:
if last_pos is not None and last_pos[0] == current_pos[0] and last_pos[1] + 1 == current_pos[1]:
adjacents += 1
last_pos = current_pos
charted_positions.sort(key=cmp_to_key(compare_col_first))
last_pos = None
for current_pos in charted_positions:
if last_pos is not None and last_pos[1] == current_pos[1] and last_pos[0] + 1 == current_pos[0]:
adjacents += 1
last_pos = current_pos
return adjacents
use_discount = True # for part two
data = []
with open("input") as f:
for line in f:
data.append(list(line.strip()))
row_count = len(data)
col_count = len(data[0])
final_sum = 0
for row in range(row_count):
for col in range(col_count):
if data[row][col] is not None:
charted_pos: list[tuple[int, int]] = []
fence_pos: list[list[tuple[int, int]]] = [[], [], [], []]
chart_result = chart_region(data, (row, col), charted_pos, fence_pos)
fences = chart_result[1]
if use_discount:
fences -= calculate_discount(fence_pos)
final_sum += chart_result[0] * fences
for pos in charted_pos:
data[pos[0]][pos[1]] = None
print(final_sum)
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