day15/solution_gemini-1.5-pro.py

def solve():
    file = "input.txt"
    with open(file, 'r') as f:
        lines = f.readlines()

    grid = [list(line.strip()) for line in lines[:-2]]
    moves = lines[-1].strip()

    def get_robot_pos(grid):
        for r in range(len(grid)):
            for c in range(len(grid[0])):
                if grid[r][c] == '@':
                    return r, c

    def is_valid(r, c, grid):
        return 0 <= r < len(grid) and 0 <= c < len(grid[0]) and grid[r][c] != '#'

    def move(grid, dr, dc):
        r, c = get_robot_pos(grid)
        nr, nc = r + dr, c + dc
        if is_valid(nr, nc, grid):
            if grid[nr][nc] == 'O':
                nnr, nnc = nr + dr, nc + dc
                if is_valid(nnr, nnc, grid) and grid[nnr][nnc] == '.':
                    grid[nnr][nnc] = 'O'
                    grid[nr][nc] = '@'
                    grid[r][c] = '.'
            elif grid[nr][nc] == '.':
                grid[nr][nc] = '@'
                grid[r][c] = '.'
        return grid

    for move_char in moves:
        if move_char == '^':
            grid = move(grid, -1, 0)
        elif move_char == 'v':
            grid = move(grid, 1, 0)
        elif move_char == '<':
            grid = move(grid, 0, -1)
        elif move_char == '>':
            grid = move(grid, 0, 1)

    gps_sum = 0
    for r in range(len(grid)):
        for c in range(len(grid[0])):
            if grid[r][c] == 'O':
                gps_sum += (r * 100) + c

    print(str(gps_sum))


    # Part 2
    grid2 = [list(line.strip()) for line in lines[:-2]]
    grid2 = [[c * 2 for c in row] for row in grid2]
    for r in range(len(grid2)):
        for c in range(len(grid2[0])):
            if grid2[r][c] == 'O':
                grid2[r][c] = '['
                grid2[r][c+1] = ']'
            elif grid2[r][c] == '@':
                grid2[r][c+1] = '.'

    def move2(grid, dr, dc):
        r, c = get_robot_pos(grid)
        nr, nc = r + dr, c + dc

        if is_valid(nr, nc, grid):
            if grid[nr][nc] == '[':
                nnr, nnc = nr + dr, nc + dc
                if is_valid(nnr, nnc, grid) and grid[nnr][nnc] == '.':
                    if is_valid(nnr, nnc + 1, grid) and grid[nnr][nnc + 1] == '.':
                        grid[nnr][nnc] = '['
                        grid[nnr][nnc + 1] = ']'
                        grid[nr][nc] = '@'
                        grid[nr][nc + 1] = '.'
                        grid[r][c] = '.'
                        grid[r][c + 1] = '.'

            elif grid[nr][nc] == '.':
                grid[nr][nc] = '@'
                grid[r][c] = '.'
                if grid[r][c+1] == '.':
                    grid[r][c+1] = '.'
        return grid

    for move_char in moves:
        if move_char == '^':
            grid2 = move2(grid2, -1, 0)
        elif move_char == 'v':
            grid2 = move2(grid2, 1, 0)
        elif move_char == '<':
            grid2 = move2(grid2, 0, -1)
        elif move_char == '>':
            grid2 = move2(grid2, 0, 1)

    gps_sum2 = 0
    for r in range(len(grid2)):
        for c in range(len(grid2[0])):
            if grid2[r][c] == '[':
                gps_sum2 += (r * 100) + c

    print(str(gps_sum2))

solve()