advent_of_code/2021/13/13_2.py

#!/usr/bin/env python
# 2021 - Advent Of Code - 13 part 2
# 2022: cheat for pylint to start fresh for 2022
# pylint: disable=unnecessary-list-index-lookup


def parse_file(file):
    parsed_dots = []
    parsed_folds = []
    with open(file, encoding="utf-8") as f:
        for line in f.readlines():
            if line.startswith('fold along '):
                _, f = line.strip().split('fold along ')
                parsed_folds.append(f.split('='))
            elif line == '\n':
                pass
            else:
                dot = [int(d) for d in line.strip().split(',')]
                parsed_dots.append(dot)
        return parsed_dots, parsed_folds


def find_max(dot_list):
    mx = 0
    my = 0
    for d in dot_list:
        if d[0] > mx:
            mx = d[0]
        if d[1] > my:
            my = d[1]

    return mx, my


def place_dots(g, dots_list):
    for dot in dots_list:
        g[dot[1]][dot[0]] = 1


def print_grid(g):
    for y, _ in enumerate(g):
        for x, _ in enumerate(g[y]):
            if g[y][x] == 1:
                print('#', end='')
            else:
                print('.', end='')
        print()


def fold_horizontally(g, fold_y, g_maxy):
    print(f'folding y={fold_y}')
    for y in range(fold_y, g_maxy+1):
        folding_dist = y - fold_y
        new_y = fold_y - folding_dist

        # place new dots
        for x, _ in enumerate(g[y]):
            if g[y][x] == 1:
                g[new_y][x] = 1

    # cut the other half of the grid
    for _ in range(fold_y+1):
        g.pop()
    return fold_y-1


def fold_vertically(g, fold_x, g_maxx):
    print(f'folding x={fold_x}')
    for y, _ in enumerate(g):
        # place new dots
        for x in range(fold_x, g_maxx+1):
            folding_dist = x - fold_x
            new_x = fold_x - folding_dist
            if g[y][x] == 1:
                g[y][new_x] = 1

        # cut the other half of the grid
        g[y] = g[y][:fold_x]
    return fold_x-1


def count_dots(g):
    count = 0
    for y, _ in enumerate(g):
        for x, _ in enumerate(g[y]):
            if g[y][x] == 1:
                count += 1

    return count


# dots, folds = parse_file('input_example.txt')
dots, folds = parse_file('input.txt')

maxx, maxy = find_max(dots)
grid = [[0] * (maxx+1) for _ in range(maxy+1)]

place_dots(grid, dots)
print(f'grid size: {maxx}, {maxy}')
print(f'real grid size: {len(grid[0])}, {len(grid)}')
print()

for fold in folds:
    if fold[0] == 'x':
        maxx = fold_vertically(grid, int(fold[1]), maxx)
    else:
        maxy = fold_horizontally(grid, int(fold[1]), maxy)
    print(f'grid size: {maxx}, {maxy}')
    print(f'real grid size: {len(grid[0])}, {len(grid)}')
    print()

print_grid(grid)