89 lines
2.4 KiB
C
89 lines
2.4 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdbool.h>
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#include "../../lib/aoc.h"
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typedef struct Map {
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char *data;
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int data_length;
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int width;
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int height;
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int current_level;
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int positions[10000];
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int positions_count;
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} Map;
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void ascend(Map *map, bool dedupe) {
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char search_for = map->current_level + 1 + '0';
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int positions[10000];
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int positions_count = 0;
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for (int i = 0; i < map->positions_count; i++) {
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int p = map->positions[i];
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if (p - map->width >= 0 && map->data[p - map->width] == search_for) positions[positions_count++] = p - map->width;
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if (map->data[p - 1] == search_for) positions[positions_count++] = p - 1;
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if (map->data[p + 1] == search_for) positions[positions_count++] = p + 1;
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if (p + map->width < map->data_length && map->data[p + map->width] == search_for) positions[positions_count++] = p + map->width;
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}
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if (dedupe) {
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qsort(positions, positions_count, sizeof(int), aoc_sort_int);
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int deduped_positions[10000];
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int deduped_positions_count = 0;
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for (int i = 0; i < positions_count - 1; i++) {
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if (positions[i] != positions[i+1]) {
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deduped_positions[deduped_positions_count++] = positions[i];
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}
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}
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deduped_positions[deduped_positions_count++] = positions[positions_count - 1];
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map->positions_count = deduped_positions_count;
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memcpy(&(map->positions), &deduped_positions, deduped_positions_count * sizeof(int));
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map->current_level++;
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} else {
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map->positions_count = positions_count;
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memcpy(&(map->positions), &positions, positions_count * sizeof(int));
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map->current_level++;
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}
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}
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int calculate_score(Map *map, int index, bool dedupe) {
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if (map->data[index] != '0') return 0;
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map->current_level = 0;
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map->positions[0] = index;
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map->positions_count = 1;
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for (int i = 0; i < 9; i++) {
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ascend(map, dedupe);
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}
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return map->positions_count;
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}
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int main() {
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char *input = aoc_read_input();
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int input_length = strlen(input);
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Map m;
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m.data = input;
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m.data_length = input_length;
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m.width = strchr(input, '\n') - input + 1;
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m.height = input_length - m.width;
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int score = 0;
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int big_score = 0;
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for (int i = 0; i < input_length; i++) {
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score += calculate_score(&m, i, true);
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big_score += calculate_score(&m, i, false);
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}
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printf("Part 1: %d\n", score);
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printf("Part 2: %d\n", big_score);
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aoc_free();
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return 0;
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}
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