101 lines
2.9 KiB
C
101 lines
2.9 KiB
C
/* ************************************************************************** */
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/* */
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/* ::: :::::::: */
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/* solution.c :+: :+: :+: */
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/* +:+ +:+ +:+ */
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/* By: tischmid <marvin@42.fr> +#+ +:+ +#+ */
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/* +#+#+#+#+#+ +#+ */
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/* Created: 2023/04/04 21:46:57 by tischmid #+# #+# */
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/* Updated: 2023/04/05 11:18:21 by tischmid ### ########.fr */
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/* */
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/* ************************************************************************** */
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#include "solution.h"
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// Replace each cell by the number of obstacles a rectangle starting
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// from the top left cell, filling the board until the cell in question,
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// covers. Border is inclusive. This will enable us to check if a given
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// square contains obstacles or not in O(1) time, instead of O(n^2),
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// namely by summing up the corner cells alternatingly (+, -, +, -, clockwise).
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void preprocess_map(t_map *map)
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{
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int is_obstacle;
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int idx;
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idx = 0;
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while (idx < map->meta.width * map->meta.height)
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{
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is_obstacle = get_cell(map, idx, 0, 0) == map->meta.obstacle;
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map->data[idx] = is_obstacle + \
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get_cell(map, idx, 0, -1) + \
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get_cell(map, idx, -1, 0) - \
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get_cell(map, idx, -1, -1);
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idx++;
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}
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}
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int count_obstacles(t_map *map, int idx, int sq_size)
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{
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int alternat_corner_sum;
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if (sq_size == 0)
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return (0);
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if (sq_size == 1)
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return (get_cell(map, idx, 0, 0));
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if (idx + (sq_size - 1) * (map->meta.width + 1)
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> map->meta.width * map->meta.height)
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return (-1);
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alternat_corner_sum = get_cell(map, idx, -1, -1) - \
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get_cell(map, idx, -1, sq_size - 1) + \
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get_cell(map, idx, sq_size - 1, sq_size - 1) - \
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get_cell(map, idx, sq_size - 1, -1);
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return (alternat_corner_sum);
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}
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void fill_with_full(t_map *map, int sq_idx, int sq_size)
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{
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int idx;
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int idx_row;
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int idx_col;
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int sq_row;
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int sq_col;
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sq_row = itor(sq_idx, map->meta.width);
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sq_col = itoc(sq_idx, map->meta.width);
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idx = 0;
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while (idx < map->meta.width * map->meta.height)
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{
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idx_row = itor(idx, map->meta.width);
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idx_col = itoc(idx, map->meta.width);
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if (idx_row >= sq_row && idx_row < sq_row + sq_size
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&& idx_col >= sq_col && idx_col < sq_col + sq_size)
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map->data[idx] = map->meta.full;
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else
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map->data[idx] = map->copy[idx];
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idx++;
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}
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}
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void solve(t_map *map)
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{
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int idx;
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int sq_idx;
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int sq_size;
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preprocess_map(map);
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idx = 0;
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sq_size = 0;
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sq_idx = 0;
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while (idx < map->meta.width * map->meta.height)
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{
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while (count_obstacles(map, idx, sq_size) == 0)
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{
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sq_idx = idx;
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sq_size++;
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}
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idx++;
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}
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sq_size--;
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fill_with_full(map, sq_idx, sq_size);
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}
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