112 lines
3.1 KiB
C
112 lines
3.1 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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char *target_string = "XMAS";
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#define TARGET_STRING_LENGTH 4
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typedef struct Puzzle {
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char *text;
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int width;
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int height;
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} Puzzle;
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char puzzle_char_at(Puzzle *puzzle, int row, int column) {
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return puzzle->text[column + (puzzle->width * row)];
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}
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bool puzzle_inbounds(Puzzle *puzzle, int row, int column) {
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return row < puzzle->height && row >= 0 && column >= 0 && column < puzzle->width;
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}
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int target_string_count(Puzzle *puzzle, int index) {
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if (puzzle->text[index] != target_string[0]) return 0;
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int count = 0;
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int row = index / puzzle->width;
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int column = index % puzzle->width;
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// right
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for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
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if (!puzzle_inbounds(puzzle, row, column + i)) break;
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if (puzzle_char_at(puzzle, row, column + i) != target_string[i]) break;
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if (i == TARGET_STRING_LENGTH - 1) count += 1;
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}
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// down right
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for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
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if (!puzzle_inbounds(puzzle, row + i, column + i)) break;
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if (puzzle_char_at(puzzle, row + i, column + i) != target_string[i]) break;
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if (i == TARGET_STRING_LENGTH - 1) count += 1;
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}
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// down
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for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
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if (!puzzle_inbounds(puzzle, row + i, column)) break;
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if (puzzle_char_at(puzzle, row + i, column) != target_string[i]) break;
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if (i == TARGET_STRING_LENGTH - 1) count += 1;
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}
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// down left
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for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
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if (!puzzle_inbounds(puzzle, row + i, column - i)) break;
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if (puzzle_char_at(puzzle, row + i, column - i) != target_string[i]) break;
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if (i == TARGET_STRING_LENGTH - 1) count += 1;
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}
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// left
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for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
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if (!puzzle_inbounds(puzzle, row, column - i)) break;
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if (puzzle_char_at(puzzle, row, column - i) != target_string[i]) break;
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if (i == TARGET_STRING_LENGTH - 1) count += 1;
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}
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// up left
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for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
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if (!puzzle_inbounds(puzzle, row - i, column - i)) break;
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if (puzzle_char_at(puzzle, row - i, column - i) != target_string[i]) break;
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if (i == TARGET_STRING_LENGTH - 1) count += 1;
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}
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// up
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for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
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if (!puzzle_inbounds(puzzle, row - i, column)) break;
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if (puzzle_char_at(puzzle, row - i, column) != target_string[i]) break;
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if (i == TARGET_STRING_LENGTH - 1) count += 1;
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}
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// up right
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for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
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if (!puzzle_inbounds(puzzle, row - i, column + i)) break;
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if (puzzle_char_at(puzzle, row - i, column + i) != target_string[i]) break;
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if (i == TARGET_STRING_LENGTH - 1) count += 1;
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}
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return 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 width = strchr(input, '\n') - input + 1;
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int height = strlen(input) / width;
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Puzzle p;
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p.text = input;
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p.width = width;
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p.height = height;
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int sum = 0;
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for (int i = 0; i < strlen(input); i++) {
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sum += target_string_count(&p, i);
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}
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printf("Part 1: %d\n", sum);
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// printf("Part 2: %d\n", cond_sum);
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aoc_free();
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return 0;
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}
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