day12/solution_gpt-4o.py

file = "input.txt"

def read_input(file):
    with open(file, 'r') as f:
        return [line.strip() for line in f]

def get_neighbors(x, y, max_x, max_y):
    neighbors = []
    if x > 0:
        neighbors.append((x - 1, y))
    if x < max_x - 1:
        neighbors.append((x + 1, y))
    if y > 0:
        neighbors.append((x, y - 1))
    if y < max_y - 1:
        neighbors.append((x, y + 1))
    return neighbors

def flood_fill(grid, x, y, visited):
    plant_type = grid[x][y]
    stack = [(x, y)]
    region = []
    while stack:
        cx, cy = stack.pop()
        if (cx, cy) in visited:
            continue
        visited.add((cx, cy))
        region.append((cx, cy))
        for nx, ny in get_neighbors(cx, cy, len(grid), len(grid[0])):
            if grid[nx][ny] == plant_type and (nx, ny) not in visited:
                stack.append((nx, ny))
    return region

def calculate_perimeter(region, grid):
    perimeter = 0
    for x, y in region:
        for nx, ny in get_neighbors(x, y, len(grid), len(grid[0])):
            if grid[nx][ny] != grid[x][y]:
                perimeter += 1
    return perimeter

def calculate_sides(region, grid):
    sides = set()
    for x, y in region:
        for nx, ny in get_neighbors(x, y, len(grid), len(grid[0])):
            if grid[nx][ny] != grid[x][y]:
                sides.add(((x, y), (nx, ny)))
    return len(sides)

def calculate_total_price(grid, use_sides=False):
    visited = set()
    total_price = 0
    for x in range(len(grid)):
        for y in range(len(grid[0])):
            if (x, y) not in visited:
                region = flood_fill(grid, x, y, visited)
                area = len(region)
                if use_sides:
                    sides = calculate_sides(region, grid)
                    price = area * sides
                else:
                    perimeter = calculate_perimeter(region, grid)
                    price = area * perimeter
                total_price += price
    return total_price

def main():
    grid = read_input(file)
    # Part 1
    total_price_part1 = calculate_total_price(grid, use_sides=False)
    print(total_price_part1)
    
    # Part 2
    total_price_part2 = calculate_total_price(grid, use_sides=True)
    print(total_price_part2)

main()